(1) debian/postrm and (2) debian/localepurge.config in localepurge before 0.7.3.2 use tempfile to create a safe temporary file but appends a suffix to the original filename and writes to this new filename, which allows local users to overwrite arbitrary files via a symlink attack on the new filename.

os-prober in os-prober 1.17 allows local users to overwrite arbitrary files via a symlink attack on the (1) /tmp/mounted-map or (2) /tmp/raided-map temporary file. NOTE: the vendor disputes this issue, stating "the insecure code path should only ever run inside a d-i environment, which has no non-root users.

maps/Info/combine.pl in CrossFire crossfire-maps 1.11.0 allows local users to overwrite arbitrary files via a symlink attack on a temporary file.

/bin/login in shadow 4.0.18.1 in Debian GNU/Linux, and probably other Linux distributions, allows local users in the utmp group to overwrite arbitrary files via a symlink attack on a temporary file referenced in a line (aka ut_line) field in a utmp entry.

It was found that the fix for CVE-2018-10927, CVE-2018-10928, CVE-2018-10929, CVE-2018-10930, and CVE-2018-10926 was incomplete. A remote, authenticated attacker could use one of these flaws to execute arbitrary code, create arbitrary files, or cause denial of service on glusterfs server nodes via symlinks to relative paths.

(1) xenbaked and (2) xenmon.py in Xen 3.1 and earlier allow local users to truncate arbitrary files via a symlink attack on /tmp/xenq-shm.

MySQL before 5.0.67 allows local users to bypass certain privilege checks by calling CREATE TABLE on a MyISAM table with modified (1) DATA DIRECTORY or (2) INDEX DIRECTORY arguments that are originally associated with pathnames without symlinks, and that can point to tables created at a future time at which a pathname is modified to contain a symlink to a subdirectory of the MySQL home data directory. NOTE: this vulnerability exists because of an incomplete fix for CVE-2008-4097.

RARLAB UnRAR before 6.12 on Linux and UNIX allows directory traversal to write to files during an extract (aka unpack) operation, as demonstrated by creating a ~/.ssh/authorized_keys file. NOTE: WinRAR and Android RAR are unaffected.

qemu-make-debian-root in qemu 0.9.1-5 on Debian GNU/Linux allows local users to overwrite arbitrary files via a symlink attack on temporary files and directories.

The to-upgrade plugin in feta 1.4.16 allows local users to overwrite arbitrary files via a symlink on the (1) /tmp/feta.install.$USER and (2) /tmp/feta.avail.$USER temporary files.

The save function in br/prefmanager.d in projectl 1.001 creates a projectL.prf file in the current working directory, which allows local users to overwrite arbitrary files via a symlink attack.

In KDE Ark before 20.08.1, a crafted TAR archive with symlinks can install files outside the extraction directory, as demonstrated by a write operation to a user's home directory.

w_editeur.c in XWine 1.0.1 for Debian GNU/Linux allows local users to overwrite or print arbitrary files via a symlink attack on the temporaire temporary file. NOTE: some of these details are obtained from third party information.

The write_array_file function in utils/include.pl in GForge 4.5.14 updates configuration files by truncating them to zero length and then writing new data, which might allow attackers to bypass intended access restrictions or have unspecified other impact in opportunistic circumstances.

guilt 0.27 allows local users to overwrite arbitrary files via a symlink attack on a guilt.log.[PID] temporary file.

vobcopy 0.5.14 allows local users to append data to an arbitrary file, or create an arbitrary new file, via a symlink attack on the (1) /tmp/vobcopy.bla or (2) /tmp/vobcopy_0.5.14.log temporary file.

Insufficient data validation in installer in Google Chrome prior to 86.0.4240.183 allowed a local attacker to potentially elevate privilege via a crafted filesystem.

Samba before versions 4.6.1, 4.5.7 and 4.4.11 are vulnerable to a malicious client using a symlink race to allow access to areas of the server file system not exported under the share definition.

NLnet Labs Unbound, up to and including version 1.12.0, and NLnet Labs NSD, up to and including version 4.3.3, contain a local vulnerability that would allow for a local symlink attack. When writing the PID file, Unbound and NSD create the file if it is not there, or open an existing file for writing. In case the file was already present, they would follow symlinks if the file happened to be a symlink instead of a regular file. An additional chown of the file would then take place after it was written, making the user Unbound/NSD is supposed to run as the new owner of the file. If an attacker has local access to the user Unbound/NSD runs as, she could create a symlink in place of the PID file pointing to a file that she would like to erase. If then Unbound/NSD is killed and the PID file is not cleared, upon restarting with root privileges, Unbound/NSD will rewrite any file pointed at by the symlink. This is a local vulnerability that could create a Denial of Service of the system Unbound/NSD is running on. It requires an attacker having access to the limited permission user Unbound/NSD runs as and point through the symlink to a critical file on the system.

atop: symlink attack possible due to insecure tempfile handling

Hardlink before 0.1.2 operates on full file system objects path names which can allow a local attacker to use this flaw to conduct symlink attacks.

foomatic-rip filter, all versions, used insecurely creates temporary files for storage of PostScript data by rendering the data when the debug mode was enabled. This flaw may be exploited by a local attacker to conduct symlink attacks by overwriting arbitrary files accessible with the privileges of the user running the foomatic-rip universal print filter.

fr-archive-libarchive.c in GNOME file-roller through 3.36.1 allows Directory Traversal during extraction because it lacks a check of whether a file's parent is a symlink to a directory outside of the intended extraction location.

In libXfont before 1.5.4 and libXfont2 before 2.0.3, a local attacker can open (but not read) files on the system as root, triggering tape rewinds, watchdogs, or similar mechanisms that can be triggered by opening files.

Cool Projects TarDiff allows local users to write to arbitrary files via a symlink attack on a pathname in a /tmp/tardiff-$$ temporary directory.

The npm package "tar" (aka node-tar) before versions 4.4.16, 5.0.8, and 6.1.7 has an arbitrary file creation/overwrite and arbitrary code execution vulnerability. node-tar aims to guarantee that any file whose location would be modified by a symbolic link is not extracted. This is, in part, achieved by ensuring that extracted directories are not symlinks. Additionally, in order to prevent unnecessary stat calls to determine whether a given path is a directory, paths are cached when directories are created. This logic was insufficient when extracting tar files that contained both a directory and a symlink with the same name as the directory, where the symlink and directory names in the archive entry used backslashes as a path separator on posix systems. The cache checking logic used both `\` and `/` characters as path separators, however `\` is a valid filename character on posix systems. By first creating a directory, and then replacing that directory with a symlink, it was thus possible to bypass node-tar symlink checks on directories, essentially allowing an untrusted tar file to symlink into an arbitrary location and subsequently extracting arbitrary files into that location, thus allowing arbitrary file creation and overwrite. Additionally, a similar confusion could arise on case-insensitive filesystems. If a tar archive contained a directory at `FOO`, followed by a symbolic link named `foo`, then on case-insensitive file systems, the creation of the symbolic link would remove the directory from the filesystem, but _not_ from the internal directory cache, as it would not be treated as a cache hit. A subsequent file entry within the `FOO` directory would then be placed in the target of the symbolic link, thinking that the directory had already been created. These issues were addressed in releases 4.4.16, 5.0.8 and 6.1.7. The v3 branch of node-tar has been deprecated and did not receive patches for these issues. If you are still using a v3 release we recommend you update to a more recent version of node-tar. If this is not possible, a workaround is available in the referenced GHSA-9r2w-394v-53qc.

An issue was discovered in GNOME GLib before 2.66.8. When g_file_replace() is used with G_FILE_CREATE_REPLACE_DESTINATION to replace a path that is a dangling symlink, it incorrectly also creates the target of the symlink as an empty file, which could conceivably have security relevance if the symlink is attacker-controlled. (If the path is a symlink to a file that already exists, then the contents of that file correctly remain unchanged.)

An improper link resolution flaw while extracting an archive can lead to changing the access control list (ACL) of the target of the link. An attacker may provide a malicious archive to a victim user, who would trigger this flaw when trying to extract the archive. A local attacker may use this flaw to change the ACL of a file on the system and gain more privileges.

Git is an open-source distributed revision control system. In affected versions of Git a specially crafted repository that contains symbolic links as well as files using a clean/smudge filter such as Git LFS, may cause just-checked out script to be executed while cloning onto a case-insensitive file system such as NTFS, HFS+ or APFS (i.e. the default file systems on Windows and macOS). Note that clean/smudge filters have to be configured for that. Git for Windows configures Git LFS by default, and is therefore vulnerable. The problem has been patched in the versions published on Tuesday, March 9th, 2021. As a workaound, if symbolic link support is disabled in Git (e.g. via `git config --global core.symlinks false`), the described attack won't work. Likewise, if no clean/smudge filters such as Git LFS are configured globally (i.e. _before_ cloning), the attack is foiled. As always, it is best to avoid cloning repositories from untrusted sources. The earliest impacted version is 2.14.2. The fix versions are: 2.30.1, 2.29.3, 2.28.1, 2.27.1, 2.26.3, 2.25.5, 2.24.4, 2.23.4, 2.22.5, 2.21.4, 2.20.5, 2.19.6, 2.18.5, 2.17.62.17.6.

storeBackup.pl in storeBackup through 3.5 relies on the /tmp/storeBackup.lock pathname, which allows symlink attacks that possibly lead to privilege escalation. (Local users can also create a plain file named /tmp/storeBackup.lock to block use of storeBackup until an admin manually deletes that file.)

GNOME Display Manager (gdm) 2.x before 2.32.1 allows local users to change the ownership of arbitrary files via a symlink attack on a (1) dmrc or (2) face icon file under /var/cache/gdm/.

Windows Setup Elevation of Privilege Vulnerability

Windows 10 Update Assistant Elevation of Privilege Vulnerability

GNOME Display Manager (gdm) before 2.21.1 allows local users to change permissions of arbitrary directories via a symlink attack on /tmp/.X11-unix/.

(1) contrib/gforge-3.0-cronjobs.patch, (2) cronjobs/homedirs.php, (3) deb-specific/fileforge.pl, (4) deb-specific/group_dump_update.pl, (5) deb-specific/ssh_dump_update.pl, (6) deb-specific/user_dump_update.pl, (7) plugins/scmbzr/common/BzrPlugin.class.php, (8) plugins/scmcvs/common/CVSPlugin.class.php, (9) plugins/scmcvs/cronjobs/cvs.php, (10) plugins/scmcvs/cronjobs/ssh_create.php, (11) plugins/scmgit/common/GitPlugin.class.php, (12) plugins/scmsvn/common/SVNPlugin.class.php, (13) plugins/wiki/cronjobs/create_groups.php, (14) utils/cvs1/cvscreate.sh, and (15) utils/include.pl in FusionForge 5.0, 5.1, and 5.2 allows local users to change arbitrary file permissions, obtain sensitive information, and have other unspecified impacts via a (1) symlink or (2) hard link attack on certain files.

The (1) tomcat5, (2) tomcat6, and (3) tomcat7 init scripts, as used in the RPM distribution of Tomcat for JBoss Enterprise Web Server 1.0.2 and 2.0.0, and Red Hat Enterprise Linux 5 and 6, allow local users to change the ownership of arbitrary files via a symlink attack on (a) tomcat5-initd.log, (b) tomcat6-initd.log, (c) catalina.out, or (d) tomcat7-initd.log.

Monkey HTTP Daemon 0.9.3 might allow local users to overwrite arbitrary files via a symlink attack on a PID file, as demonstrated by a pathname different from the default /var/run/monkey.pid pathname.

The open_log function in log.c in Exim 4.72 and earlier does not check the return value from (1) setuid or (2) setgid system calls, which allows local users to append log data to arbitrary files via a symlink attack.

mysqld_safe in Oracle MySQL through 5.5.51, 5.6.x through 5.6.32, and 5.7.x through 5.7.14; MariaDB; Percona Server before 5.5.51-38.2, 5.6.x before 5.6.32-78-1, and 5.7.x before 5.7.14-8; and Percona XtraDB Cluster before 5.5.41-37.0, 5.6.x before 5.6.32-25.17, and 5.7.x before 5.7.14-26.17, when using file-based logging, allows local users with access to the mysql account to gain root privileges via a symlink attack on error logs and possibly other files.

UNIX Symbolic Link (Symlink) Following vulnerability in the cronjob shipped with nagios of SUSE Linux Enterprise Server 12, SUSE Linux Enterprise Server 11; openSUSE Factory allows local attackers to cause cause DoS or potentially escalate privileges by winning a race. This issue affects: SUSE Linux Enterprise Server 12 nagios version 3.5.1-5.27 and prior versions. SUSE Linux Enterprise Server 11 nagios version 3.0.6-1.25.36.3.1 and prior versions. openSUSE Factory nagios version 4.4.5-2.1 and prior versions.

elf/dl-load.c in ld.so in the GNU C Library (aka glibc or libc6) through 2.11.2, and 2.12.x through 2.12.1, does not properly handle a value of $ORIGIN for the LD_AUDIT environment variable, which allows local users to gain privileges via a crafted dynamic shared object (DSO) located in an arbitrary directory.

BSD pppd allows local users to change the permissions of arbitrary files via a symlink attack on a file that is specified as a tty device.

NVIDIA GeForce Experience before 3.18 contains a vulnerability when ShadowPlay or GameStream is enabled. When an attacker has access to the system and creates a hard link, the software does not check for hard link attacks. This behavior may lead to code execution, denial of service, or escalation of privileges.

pam_motd (aka the MOTD module) in libpam-modules before 1.1.0-2ubuntu1.1 in PAM on Ubuntu 9.10 and libpam-modules before 1.1.1-2ubuntu5 in PAM on Ubuntu 10.04 LTS allows local users to change the ownership of arbitrary files via a symlink attack on .cache in a user's home directory, related to "user file stamps" and the motd.legal-notice file.

Chip Salzenberg Deliver allows local users to cause a denial of service, obtain sensitive information, and possibly change the ownership of arbitrary files via a symlink attack on an unspecified file.

The prerm script in axyl 2.1.7 allows local users to overwrite arbitrary files via a symlink attack on the axyl.conf temporary file.

flamethrower in flamethrower 0.1.8 allows local users to overwrite arbitrary files via a symlink attack on a /tmp/multicast.tar.##### temporary file.

By exploiting a time of check to time of use (TOCTOU) race condition during the Endpoint Security for Linux Threat Prevention and Firewall (ENSL TP/FW) installation process, a local user can perform a privilege escalation attack to obtain administrator privileges for the purpose of executing arbitrary code through insecure use of predictable temporary file locations.

vdrleaktest in Video Disk Recorder (aka vdr-dbg or vdr) 1.6.0 allows local users to overwrite arbitrary files via a symlink attack on the /tmp/memleaktest.log temporary file.

find_flags in Kitware GCC-XML (gccxml) 0.9.0 allows local users to overwrite arbitrary files via a symlink attack on a /tmp/*.cxx temporary file.