In the Linux kernel, the following vulnerability has been resolved: drm/drm_file: Fix pid refcounting race <maarten.lankhorst@linux.intel.com>, Maxime Ripard <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de> filp->pid is supposed to be a refcounted pointer; however, before this patch, drm_file_update_pid() only increments the refcount of a struct pid after storing a pointer to it in filp->pid and dropping the dev->filelist_mutex, making the following race possible: process A process B ========= ========= begin drm_file_update_pid mutex_lock(&dev->filelist_mutex) rcu_replace_pointer(filp->pid, <pid B>, 1) mutex_unlock(&dev->filelist_mutex) begin drm_file_update_pid mutex_lock(&dev->filelist_mutex) rcu_replace_pointer(filp->pid, <pid A>, 1) mutex_unlock(&dev->filelist_mutex) get_pid(<pid A>) synchronize_rcu() put_pid(<pid B>) *** pid B reaches refcount 0 and is freed here *** get_pid(<pid B>) *** UAF *** synchronize_rcu() put_pid(<pid A>) As far as I know, this race can only occur with CONFIG_PREEMPT_RCU=y because it requires RCU to detect a quiescent state in code that is not explicitly calling into the scheduler. This race leads to use-after-free of a "struct pid". It is probably somewhat hard to hit because process A has to pass through a synchronize_rcu() operation while process B is between mutex_unlock() and get_pid(). Fix it by ensuring that by the time a pointer to the current task's pid is stored in the file, an extra reference to the pid has been taken. This fix also removes the condition for synchronize_rcu(); I think that optimization is unnecessary complexity, since in that case we would usually have bailed out on the lockless check above.

The receive_msg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to execute arbitrary code or cause a denial of service (use-after-free) via vectors involving BDAT commands.

In the Linux kernel, the following vulnerability has been resolved: atm: iphase: fix possible use-after-free in ia_module_exit() This module's remove path calls del_timer(). However, that function does not wait until the timer handler finishes. This means that the timer handler may still be running after the driver's remove function has finished, which would result in a use-after-free. Fix by calling del_timer_sync(), which makes sure the timer handler has finished, and unable to re-schedule itself.

In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: Fix seg fault in rxe_comp_queue_pkt In rxe_comp_queue_pkt() an incoming response packet skb is enqueued to the resp_pkts queue and then a decision is made whether to run the completer task inline or schedule it. Finally the skb is dereferenced to bump a 'hw' performance counter. This is wrong because if the completer task is already running in a separate thread it may have already processed the skb and freed it which can cause a seg fault. This has been observed infrequently in testing at high scale. This patch fixes this by changing the order of enqueuing the packet until after the counter is accessed.

In the Linux Kernel before versions 4.20.8 and 4.19.21 a use-after-free error in the "sctp_sendmsg()" function (net/sctp/socket.c) when handling SCTP_SENDALL flag can be exploited to corrupt memory.

A use-after-free flaw was found in the Linux kernel’s PLP Rose functionality in the way a user triggers a race condition by calling bind while simultaneously triggering the rose_bind() function. This flaw allows a local user to crash or potentially escalate their privileges on the system.

In the Linux kernel, the following vulnerability has been resolved: drm/prime: Fix use after free in mmap with drm_gem_ttm_mmap drm_gem_ttm_mmap() drops a reference to the gem object on success. If the gem object's refcount == 1 on entry to drm_gem_prime_mmap(), that drop will free the gem object, and the subsequent drm_gem_object_get() will be a UAF. Fix by grabbing a reference before calling the mmap helper. This issue was forseen when the reference dropping was adding in commit 9786b65bc61ac ("drm/ttm: fix mmap refcounting"): "For that to work properly the drm_gem_object_get() call in drm_gem_ttm_mmap() must be moved so it happens before calling obj->funcs->mmap(), otherwise the gem refcount would go down to zero."

In the Linux kernel, the following vulnerability has been resolved: can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv It will trigger UAF for rx_kref of j1939_priv as following. cpu0 cpu1 j1939_sk_bind(socket0, ndev0, ...) j1939_netdev_start j1939_sk_bind(socket1, ndev0, ...) j1939_netdev_start j1939_priv_set j1939_priv_get_by_ndev_locked j1939_jsk_add ..... j1939_netdev_stop kref_put_lock(&priv->rx_kref, ...) kref_get(&priv->rx_kref, ...) REFCOUNT_WARN("addition on 0;...") ==================================================== refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 20874 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0 RIP: 0010:refcount_warn_saturate+0x169/0x1e0 Call Trace: j1939_netdev_start+0x68b/0x920 j1939_sk_bind+0x426/0xeb0 ? security_socket_bind+0x83/0xb0 The rx_kref's kref_get() and kref_put() should use j1939_netdev_lock to protect.

The init_new_context function in arch/x86/include/asm/mmu_context.h in the Linux kernel before 4.12.10 does not correctly handle errors from LDT table allocation when forking a new process, allowing a local attacker to achieve a use-after-free or possibly have unspecified other impact by running a specially crafted program. This vulnerability only affected kernels built with CONFIG_MODIFY_LDT_SYSCALL=y.

In the Linux kernel, the following vulnerability has been resolved: net: qrtr: Avoid potential use after free in MHI send It is possible that the MHI ul_callback will be invoked immediately following the queueing of the skb for transmission, leading to the callback decrementing the refcount of the associated sk and freeing the skb. As such the dereference of skb and the increment of the sk refcount must happen before the skb is queued, to avoid the skb to be used after free and potentially the sk to drop its last refcount..

.NET and Visual Studio Remote Code Execution Vulnerability

The dvb_frontend_free function in drivers/media/dvb-core/dvb_frontend.c in the Linux kernel through 4.13.11 allows local users to cause a denial of service (use-after-free and system crash) or possibly have unspecified other impact via a crafted USB device. NOTE: the function was later renamed __dvb_frontend_free.

In the Linux kernel, the following vulnerability has been resolved: regmap: set debugfs_name to NULL after it is freed There is a upstream commit cffa4b2122f5("regmap:debugfs: Fix a memory leak when calling regmap_attach_dev") that adds a if condition when create name for debugfs_name. With below function invoking logical, debugfs_name is freed in regmap_debugfs_exit(), but it is not created again because of the if condition introduced by above commit. regmap_reinit_cache() regmap_debugfs_exit() ... regmap_debugfs_init() So, set debugfs_name to NULL after it is freed.

sound/core/seq_device.c in the Linux kernel before 4.13.4 allows local users to cause a denial of service (snd_rawmidi_dev_seq_free use-after-free and system crash) or possibly have unspecified other impact via a crafted USB device.

sound/usb/mixer.c in the Linux kernel before 4.13.8 allows local users to cause a denial of service (snd_usb_mixer_interrupt use-after-free and system crash) or possibly have unspecified other impact via a crafted USB device.

The usb_serial_console_disconnect function in drivers/usb/serial/console.c in the Linux kernel before 4.13.8 allows local users to cause a denial of service (use-after-free and system crash) or possibly have unspecified other impact via a crafted USB device, related to disconnection and failed setup.

A use-after-free vulnerability was found in the cxgb4 driver in the Linux kernel. The bug occurs when the cxgb4 device is detaching due to a possible rearming of the flower_stats_timer from the work queue. This flaw allows a local user to crash the system, causing a denial of service condition.

Race condition in the NPObjWrapper_NewResolve function in modules/plugin/base/src/nsJSNPRuntime.cpp in xul.dll in Mozilla Firefox 3 before 3.0.11 might allow remote attackers to execute arbitrary code via a page transition during Java applet loading, related to a use-after-free vulnerability for memory associated with a destroyed Java object.

liblivemedia in Live555 before 2019.02.03 mishandles the termination of an RTSP stream after RTP/RTCP-over-RTSP has been set up, which could lead to a Use-After-Free error that causes the RTSP server to crash (Segmentation fault) or possibly have unspecified other impact.

A use-after-free flaw was found in fs/userfaultfd.c in the Linux kernel before 4.13.6. The issue is related to the handling of fork failure when dealing with event messages. Failure to fork correctly can lead to a situation where a fork event will be removed from an already freed list of events with userfaultfd_ctx_put().

Use after free in libxml2 before 2.9.5, as used in Google Chrome prior to 63.0.3239.84 and other products, allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

The sctp_do_peeloff function in net/sctp/socket.c in the Linux kernel before 4.14 does not check whether the intended netns is used in a peel-off action, which allows local users to cause a denial of service (use-after-free and system crash) or possibly have unspecified other impact via crafted system calls.

Use-after-free vulnerability in Samba 4.x before 4.7.3 allows remote attackers to execute arbitrary code via a crafted SMB1 request.

A use after free in V8 in Google Chrome prior to 62.0.3202.89 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

A use-after-free vulnerability was found in the cyttsp4_core driver in the Linux kernel. This issue occurs in the device cleanup routine due to a possible rearming of the watchdog_timer from the workqueue. This could allow a local user to crash the system, causing a denial of service.

The KVM implementation in the Linux kernel through 4.20.5 has a Use-after-Free.

In the Linux kernel, the following vulnerability has been resolved: staging: greybus: uart: fix tty use after free User space can hold a tty open indefinitely and tty drivers must not release the underlying structures until the last user is gone. Switch to using the tty-port reference counter to manage the life time of the greybus tty state to avoid use after free after a disconnect.

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: msft: fix slab-use-after-free in msft_do_close() Tying the msft->data lifetime to hdev by freeing it in hci_release_dev() to fix the following case: [use] msft_do_close() msft = hdev->msft_data; if (!msft) ...(1) <- passed. return; mutex_lock(&msft->filter_lock); ...(4) <- used after freed. [free] msft_unregister() msft = hdev->msft_data; hdev->msft_data = NULL; ...(2) kfree(msft); ...(3) <- msft is freed. ================================================================== BUG: KASAN: slab-use-after-free in __mutex_lock_common kernel/locking/mutex.c:587 [inline] BUG: KASAN: slab-use-after-free in __mutex_lock+0x8f/0xc30 kernel/locking/mutex.c:752 Read of size 8 at addr ffff888106cbbca8 by task kworker/u5:2/309

ReadOneJNGImage in coders/png.c in GraphicsMagick 1.3.26 has a use-after-free issue when the height or width is zero, related to ReadJNGImage.

In the Linux kernel, the following vulnerability has been resolved: kprobes: Fix possible use-after-free issue on kprobe registration When unloading a module, its state is changing MODULE_STATE_LIVE -> MODULE_STATE_GOING -> MODULE_STATE_UNFORMED. Each change will take a time. `is_module_text_address()` and `__module_text_address()` works with MODULE_STATE_LIVE and MODULE_STATE_GOING. If we use `is_module_text_address()` and `__module_text_address()` separately, there is a chance that the first one is succeeded but the next one is failed because module->state becomes MODULE_STATE_UNFORMED between those operations. In `check_kprobe_address_safe()`, if the second `__module_text_address()` is failed, that is ignored because it expected a kernel_text address. But it may have failed simply because module->state has been changed to MODULE_STATE_UNFORMED. In this case, arm_kprobe() will try to modify non-exist module text address (use-after-free). To fix this problem, we should not use separated `is_module_text_address()` and `__module_text_address()`, but use only `__module_text_address()` once and do `try_module_get(module)` which is only available with MODULE_STATE_LIVE.

In the Linux kernel, the following vulnerability has been resolved: raid1: fix use-after-free for original bio in raid1_write_request() r1_bio->bios[] is used to record new bios that will be issued to underlying disks, however, in raid1_write_request(), r1_bio->bios[] will set to the original bio temporarily. Meanwhile, if blocked rdev is set, free_r1bio() will be called causing that all r1_bio->bios[] to be freed: raid1_write_request() r1_bio = alloc_r1bio(mddev, bio); -> r1_bio->bios[] is NULL for (i = 0; i < disks; i++) -> for each rdev in conf // first rdev is normal r1_bio->bios[0] = bio; -> set to original bio // second rdev is blocked if (test_bit(Blocked, &rdev->flags)) break if (blocked_rdev) free_r1bio() put_all_bios() bio_put(r1_bio->bios[0]) -> original bio is freed Test scripts: mdadm -CR /dev/md0 -l1 -n4 /dev/sd[abcd] --assume-clean fio -filename=/dev/md0 -ioengine=libaio -rw=write -bs=4k -numjobs=1 \ -iodepth=128 -name=test -direct=1 echo blocked > /sys/block/md0/md/rd2/state Test result: BUG bio-264 (Not tainted): Object already free ----------------------------------------------------------------------------- Allocated in mempool_alloc_slab+0x24/0x50 age=1 cpu=1 pid=869 kmem_cache_alloc+0x324/0x480 mempool_alloc_slab+0x24/0x50 mempool_alloc+0x6e/0x220 bio_alloc_bioset+0x1af/0x4d0 blkdev_direct_IO+0x164/0x8a0 blkdev_write_iter+0x309/0x440 aio_write+0x139/0x2f0 io_submit_one+0x5ca/0xb70 __do_sys_io_submit+0x86/0x270 __x64_sys_io_submit+0x22/0x30 do_syscall_64+0xb1/0x210 entry_SYSCALL_64_after_hwframe+0x6c/0x74 Freed in mempool_free_slab+0x1f/0x30 age=1 cpu=1 pid=869 kmem_cache_free+0x28c/0x550 mempool_free_slab+0x1f/0x30 mempool_free+0x40/0x100 bio_free+0x59/0x80 bio_put+0xf0/0x220 free_r1bio+0x74/0xb0 raid1_make_request+0xadf/0x1150 md_handle_request+0xc7/0x3b0 md_submit_bio+0x76/0x130 __submit_bio+0xd8/0x1d0 submit_bio_noacct_nocheck+0x1eb/0x5c0 submit_bio_noacct+0x169/0xd40 submit_bio+0xee/0x1d0 blkdev_direct_IO+0x322/0x8a0 blkdev_write_iter+0x309/0x440 aio_write+0x139/0x2f0 Since that bios for underlying disks are not allocated yet, fix this problem by using mempool_free() directly to free the r1_bio.

Use after free in PDFium in Google Chrome prior to 63.0.3239.84 allowed a remote attacker to potentially exploit heap corruption via a crafted PDF file.

A use-after-free flaw was found in the Linux kernel’s Netfilter functionality when adding a rule with NFTA_RULE_CHAIN_ID. This flaw allows a local user to crash or escalate their privileges on the system.

In lsx_aiffstartread in aiff.c in Sound eXchange (SoX) 14.4.2, there is a Use-After-Free vulnerability triggered by supplying a malformed AIFF file.

Use after free in PDFium in Google Chrome prior to 63.0.3239.84 allowed a remote attacker to potentially exploit heap corruption via a crafted PDF file.

The TIFFSetProfiles function in coders/tiff.c in ImageMagick 7.0.6 has incorrect expectations about whether LibTIFF TIFFGetField return values imply that data validation has occurred, which allows remote attackers to cause a denial of service (use-after-free after an invalid call to TIFFSetField, and application crash) via a crafted file.

A use after free in Blink in Google Chrome prior to 62.0.3202.62 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page, aka an ImageCapture NULL pointer dereference.

In the Linux kernel, the following vulnerability has been resolved: mlxsw: spectrum_acl_tcam: Fix possible use-after-free during activity update The rule activity update delayed work periodically traverses the list of configured rules and queries their activity from the device. As part of this task it accesses the entry pointed by 'ventry->entry', but this entry can be changed concurrently by the rehash delayed work, leading to a use-after-free [1]. Fix by closing the race and perform the activity query under the 'vregion->lock' mutex. [1] BUG: KASAN: slab-use-after-free in mlxsw_sp_acl_tcam_flower_rule_activity_get+0x121/0x140 Read of size 8 at addr ffff8881054ed808 by task kworker/0:18/181 CPU: 0 PID: 181 Comm: kworker/0:18 Not tainted 6.9.0-rc2-custom-00781-gd5ab772d32f7 #2 Hardware name: Mellanox Technologies Ltd. MSN3700/VMOD0005, BIOS 5.11 01/06/2019 Workqueue: mlxsw_core mlxsw_sp_acl_rule_activity_update_work Call Trace: <TASK> dump_stack_lvl+0xc6/0x120 print_report+0xce/0x670 kasan_report+0xd7/0x110 mlxsw_sp_acl_tcam_flower_rule_activity_get+0x121/0x140 mlxsw_sp_acl_rule_activity_update_work+0x219/0x400 process_one_work+0x8eb/0x19b0 worker_thread+0x6c9/0xf70 kthread+0x2c9/0x3b0 ret_from_fork+0x4d/0x80 ret_from_fork_asm+0x1a/0x30 </TASK> Allocated by task 1039: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0x8f/0xa0 __kmalloc+0x19c/0x360 mlxsw_sp_acl_tcam_entry_create+0x7b/0x1f0 mlxsw_sp_acl_tcam_vchunk_migrate_all+0x30d/0xb50 mlxsw_sp_acl_tcam_vregion_rehash_work+0x157/0x1300 process_one_work+0x8eb/0x19b0 worker_thread+0x6c9/0xf70 kthread+0x2c9/0x3b0 ret_from_fork+0x4d/0x80 ret_from_fork_asm+0x1a/0x30 Freed by task 1039: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 poison_slab_object+0x102/0x170 __kasan_slab_free+0x14/0x30 kfree+0xc1/0x290 mlxsw_sp_acl_tcam_vchunk_migrate_all+0x3d7/0xb50 mlxsw_sp_acl_tcam_vregion_rehash_work+0x157/0x1300 process_one_work+0x8eb/0x19b0 worker_thread+0x6c9/0xf70 kthread+0x2c9/0x3b0 ret_from_fork+0x4d/0x80 ret_from_fork_asm+0x1a/0x30

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF in smb2_is_network_name_deleted() Skip sessions that are being teared down (status == SES_EXITING) to avoid UAF.

Adobe Flash Player 32.0.0.238 and earlier versions, 32.0.0.207 and earlier versions have a Use after free vulnerability. Successful exploitation could lead to Arbitrary Code Execution in the context of the current user.

In the Linux kernel, the following vulnerability has been resolved: ax25: fix use-after-free bugs caused by ax25_ds_del_timer When the ax25 device is detaching, the ax25_dev_device_down() calls ax25_ds_del_timer() to cleanup the slave_timer. When the timer handler is running, the ax25_ds_del_timer() that calls del_timer() in it will return directly. As a result, the use-after-free bugs could happen, one of the scenarios is shown below: (Thread 1) | (Thread 2) | ax25_ds_timeout() ax25_dev_device_down() | ax25_ds_del_timer() | del_timer() | ax25_dev_put() //FREE | | ax25_dev-> //USE In order to mitigate bugs, when the device is detaching, use timer_shutdown_sync() to stop the timer.

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Flush pages under kvm->lock to fix UAF in svm_register_enc_region() Do the cache flush of converted pages in svm_register_enc_region() before dropping kvm->lock to fix use-after-free issues where region and/or its array of pages could be freed by a different task, e.g. if userspace has __unregister_enc_region_locked() already queued up for the region. Note, the "obvious" alternative of using local variables doesn't fully resolve the bug, as region->pages is also dynamically allocated. I.e. the region structure itself would be fine, but region->pages could be freed. Flushing multiple pages under kvm->lock is unfortunate, but the entire flow is a rare slow path, and the manual flush is only needed on CPUs that lack coherency for encrypted memory.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF in cifs_signal_cifsd_for_reconnect() Skip sessions that are being teared down (status == SES_EXITING) to avoid UAF.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF in cifs_stats_proc_write() Skip sessions that are being teared down (status == SES_EXITING) to avoid UAF.

In the Linux kernel, the following vulnerability has been resolved: x86/fpu: Keep xfd_state in sync with MSR_IA32_XFD Commit 672365477ae8 ("x86/fpu: Update XFD state where required") and commit 8bf26758ca96 ("x86/fpu: Add XFD state to fpstate") introduced a per CPU variable xfd_state to keep the MSR_IA32_XFD value cached, in order to avoid unnecessary writes to the MSR. On CPU hotplug MSR_IA32_XFD is reset to the init_fpstate.xfd, which wipes out any stale state. But the per CPU cached xfd value is not reset, which brings them out of sync. As a consequence a subsequent xfd_update_state() might fail to update the MSR which in turn can result in XRSTOR raising a #NM in kernel space, which crashes the kernel. To fix this, introduce xfd_set_state() to write xfd_state together with MSR_IA32_XFD, and use it in all places that set MSR_IA32_XFD.

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential UAF in is_valid_oplock_break() Skip sessions that are being teared down (status == SES_EXITING) to avoid UAF.

Adobe Flash Player versions 32.0.0.156 and earlier, 32.0.0.156 and earlier, and 32.0.0.156 and earlier have an use after free vulnerability. Successful exploitation could lead to arbitrary code execution.

FreeRDP is a free implementation of the Remote Desktop Protocol (RDP), released under the Apache license. Versions of FreeRDP on the 3.x release branch before beta3 are subject to a Use-After-Free in processing `RDPGFX_CMDID_RESETGRAPHICS` packets. If `context->maxPlaneSize` is 0, `context->planesBuffer` will be freed. However, without updating `context->planesBuffer`, this leads to a Use-After-Free exploit vector. In most environments this should only result in a crash. This issue has been addressed in version 3.0.0-beta3 and users of the beta 3.x releases are advised to upgrade. There are no known workarounds for this vulnerability.

A use-after-free vulnerability exists in the MediaRecorder API of Webkit WebKitGTK 2.40.5. A specially crafted web page can abuse this vulnerability to cause memory corruption and potentially arbitrary code execution. A user would need to to visit a malicious webpage to trigger this vulnerability.