Using techniques that built on the slipstream research, a malicious webpage could have scanned both an internal network's hosts as well as services running on the user's local machine utilizing WebRTC connections. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < 78.9.

The Opportunistic Encryption feature of HTTP2 (RFC 8164) allows a connection to be transparently upgraded to TLS while retaining the visual properties of an HTTP connection, including being same-origin with unencrypted connections on port 80. However, if a second encrypted port on the same IP address (e.g. port 8443) did not opt-in to opportunistic encryption; a network attacker could forward a connection from the browser to port 443 to port 8443, causing the browser to treat the content of port 8443 as same-origin with HTTP. This was resolved by disabling the Opportunistic Encryption feature, which had low usage. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

Spoofing issue in the Address Bar component of Firefox Focus for Android. This vulnerability affects Firefox < 142.

Unexpected data returned from the Safe Browsing API could have led to memory corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 102.10 and Firefox ESR < 102.10.

Spoofing issue in the Address Bar component. This vulnerability affects Firefox < 142 and Firefox ESR < 140.2.

Through use of reportValidity() and window.open(), a plain-text validation message could have been overlaid on another origin, leading to possible user confusion and spoofing attacks. This vulnerability affects Firefox < 93, Thunderbird < 91.2, and Firefox ESR < 91.2.

OCSP revocation status of recipient certificates was not checked when sending S/Mime encrypted email, and revoked certificates would be accepted. Thunderbird versions from 68 to 102.9.1 were affected by this bug. This vulnerability affects Thunderbird < 102.10.

If a MIME email combines OpenPGP and OpenPGP MIME data in a certain way Thunderbird repeatedly attempts to process and display the message, which could cause Thunderbird's user interface to lock up and no longer respond to the user's actions. An attacker could send a crafted message with this structure to attempt a DoS attack. This vulnerability affects Thunderbird < 102.8.

Certificate OCSP revocation status was not checked when verifying S/Mime signatures. Mail signed with a revoked certificate would be displayed as having a valid signature. Thunderbird versions from 68 to 102.7.0 were affected by this bug. This vulnerability affects Thunderbird < 102.7.1.

When delegating navigations to the operating system, Firefox would accept the `mk` scheme which might allow attackers to launch pages and execute scripts in Internet Explorer in unprivileged mode. *This bug only affects Firefox for Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 92, Thunderbird < 91.1, Thunderbird < 78.14, Firefox ESR < 78.14, and Firefox ESR < 91.1.

A crafted HTML email using mailbox:/// links can trigger automatic, unsolicited downloads of .pdf files to the user's desktop or home directory without prompting, even if auto-saving is disabled. This behavior can be abused to fill the disk with garbage data (e.g. using /dev/urandom on Linux) or to leak Windows credentials via SMB links when the email is viewed in HTML mode. While user interaction is required to download the .pdf file, visual obfuscation can conceal the download trigger. Viewing the email in HTML mode is enough to load external content. This vulnerability affects Thunderbird < 128.11.1 and Thunderbird < 139.0.2.

A missing check related to tex units could have led to a use-after-free and potentially exploitable crash.<br />*Note*: This advisory was added on December 13th, 2022 after we better understood the impact of the issue. The fix was included in the original release of Firefox 105. This vulnerability affects Firefox ESR < 102.6, Firefox < 105, and Thunderbird < 102.6.

When a link can be opened in an external application, Firefox for Android will, by default, prompt the user before doing so. An attacker could have bypassed this prompt, potentially exposing the user to security vulnerabilities or privacy leaks in external applications. *This bug only affects Firefox for Android. Other versions of Firefox are unaffected.* This vulnerability affects Firefox < 140.

Firefox could have incorrectly parsed a URL and rewritten it to the youtube.com domain when parsing the URL specified in an `embed` tag. This could have bypassed website security checks that restricted which domains users were allowed to embed. This vulnerability affects Firefox < 140, Firefox ESR < 128.12, Thunderbird < 140, and Thunderbird < 128.12.

Malicious scripts utilizing repetitive JavaScript alerts could prevent client user interaction in some scenarios and allow for denial of service attacks This vulnerability affects Firefox for iOS < 142.

When a ServiceWorker intercepted a request with <code>FetchEvent</code>, the origin of the request was lost after the ServiceWorker took ownership of it. This had the effect of negating SameSite cookie protections. This was addressed in the spec and then in browsers. This vulnerability affects Firefox ESR < 102.5, Thunderbird < 102.5, and Firefox < 107.

Through a series of API calls and redirects, an attacker-controlled alert dialog could have been displayed on another website (with the victim website's URL shown). This vulnerability affects Firefox < 123, Firefox ESR < 115.8, and Thunderbird < 115.8.

The incorrect object was checked for NULL in the built-in profiler, potentially leading to invalid memory access and undefined behavior. *Note:* This issue only affects the application when the profiler is running. This vulnerability affects Firefox < 123.

Freeing arbitrary <code>nsIInputStream</code>'s on a different thread than creation could have led to a use-after-free and potentially exploitable crash. This vulnerability affects Firefox ESR < 102.5, Thunderbird < 102.5, and Firefox < 107.

A null pointer dereference may have inadvertently occurred in `pk12util`, and specifically in the `SEC_ASN1DecodeItem_Util` function, when handling malformed or improperly formatted input files. This vulnerability affects Firefox < 133 and Thunderbird < 133.

Missing thread synchronization primitives could have led to a data race on members of the PlaybackParams structure. This vulnerability affects Firefox < 133 and Thunderbird < 133.

An attacker could have caused a use-after-free when accessibility was enabled, leading to a potentially exploitable crash. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Firefox ESR < 115.17, Thunderbird < 128.4, and Thunderbird < 132.

Focus was incorrectly allowing internal links to utilize the app scheme used for deeplinking, which could result in links potentially circumventing some URL safety checks This vulnerability affects Focus for iOS < 132.

A malicious website could have included an iframe with an malformed URI resulting in a non-exploitable browser crash. This vulnerability affects Firefox < 126.

Repeated writes to history interface attributes could have been used to cause a Denial of Service condition in the browser. This was addressed by introducing rate-limiting to this API. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4, and Thunderbird < 132.

A clipboard "paste" button could persist across tabs which allowed a spoofing attack. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4, and Thunderbird < 132.

Truncation of a long URL could have allowed origin spoofing in a permission prompt. This vulnerability affects Firefox < 132, Firefox ESR < 128.4, Thunderbird < 128.4, and Thunderbird < 132.

An out of bounds write in ANGLE could have allowed an attacker to corrupt memory leading to a potentially exploitable crash. This vulnerability affects Firefox < 122, Firefox ESR < 115.7, and Thunderbird < 115.7.

A use-after-free crash could have occurred on macOS if a Firefox update were being applied on a very busy system. This could have resulted in an exploitable crash. This vulnerability affects Firefox < 122.

Some WASM source files could have caused a crash when loaded in devtools. This vulnerability affects Firefox < 122.

A Linux user opening the print preview dialog could have caused the browser to crash. This vulnerability affects Firefox < 122, Firefox ESR < 115.7, and Thunderbird < 115.7.

When a parent page loaded a child in an iframe with `unsafe-inline`, the parent Content Security Policy could have overridden the child Content Security Policy. This vulnerability affects Firefox < 122, Firefox ESR < 115.7, and Thunderbird < 115.7.

A `&lt;dialog>` element could have been manipulated to paint content outside of a sandboxed iframe. This could allow untrusted content to display under the guise of trusted content. This vulnerability affects Firefox < 121.

If an attacker needed a user to load an insecure http: page and knew that user had enabled HTTPS-only mode, the attacker could have tricked the user into clicking to grant an HTTPS-only exception if they could get the user to participate in a clicking game. This vulnerability affects Firefox < 120.

When an https: web page created a pop-up from a "javascript:" URL, that pop-up was incorrectly allowed to load blockable content such as iframes from insecure http: URLs This vulnerability affects Firefox < 120.

It was possible to cause the use of a MessagePort after it had already been freed, which could potentially have led to an exploitable crash. This vulnerability affects Firefox < 120, Firefox ESR < 115.5.0, and Thunderbird < 115.5.

The executable file warning was not presented when downloading .msix, .msixbundle, .appx, and .appxbundle files, which can run commands on a user's computer. *Note: This issue only affected Windows operating systems. Other operating systems are unaffected.* This vulnerability affects Firefox < 119, Firefox ESR < 115.4, and Thunderbird < 115.4.1.

An attacker could have created a malicious link using bidirectional characters to spoof the location in the address bar when visited. This vulnerability affects Firefox < 117, Firefox ESR < 115.4, and Thunderbird < 115.4.1.

During Ion compilation, a Garbage Collection could have resulted in a use-after-free condition, allowing an attacker to write two NUL bytes, and cause a potentially exploitable crash. This vulnerability affects Firefox < 118, Firefox ESR < 115.3, and Thunderbird < 115.3.

A compromised content process could have provided malicious data in a `PathRecording` resulting in an out-of-bounds write, leading to a potentially exploitable crash in a privileged process. This vulnerability affects Firefox < 118, Firefox ESR < 115.3, and Thunderbird < 115.3.

When in an endless loop, a website specifying a custom cursor using CSS could make it look like the user is interacting with the user interface, when they are not. This could lead to a perceived broken state, especially when interactions with existing browser dialogs and warnings do not work. This vulnerability affects Firefox ESR < 78.1, Firefox < 79, and Thunderbird < 78.1.

When a link to an external protocol was clicked, a prompt was presented that allowed the user to choose what application to open it in. An attacker could induce that prompt to be associated with an origin they didn't control, resulting in a spoofing attack. This was fixed by changing external protocol prompts to be tab-modal while also ensuring they could not be incorrectly associated with a different origin. This vulnerability affects Firefox < 82.

In Network Security Services (NSS) before 3.36.7 and before 3.41.1, a malformed signature can cause a crash due to a null dereference, resulting in a Denial of Service.

Through a series of DOM manipulations, a message, over which the attacker had control of the text but not HTML or formatting, could be overlaid on top of another domain (with the new domain correctly shown in the address bar) resulting in possible user confusion. This vulnerability affects Firefox < 90.

The WebAssembly JIT could miscalculate the size of a return type, which could lead to a null read and result in a crash. *Note: This issue only affected x86-32 platforms. Other platforms are unaffected.*. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

When receiving rendering data over IPC `mStream` could have been destroyed when initialized, which could have led to a use-after-free causing a potentially exploitable crash. This vulnerability affects Firefox < 117, Firefox ESR < 102.15, Firefox ESR < 115.2, Thunderbird < 102.15, and Thunderbird < 115.2.

When `UpdateRegExpStatics` attempted to access `initialStringHeap` it could already have been garbage collected prior to entering the function, which could potentially have led to an exploitable crash. This vulnerability affects Firefox < 117, Firefox ESR < 115.2, and Thunderbird < 115.2.

When creating a callback over IPC for showing the Color Picker window, multiple of the same callbacks could have been created at a time and eventually all simultaneously destroyed as soon as one of the callbacks finished. This could have led to a use-after-free causing a potentially exploitable crash. This vulnerability affects Firefox < 117, Firefox ESR < 102.15, Firefox ESR < 115.2, Thunderbird < 102.15, and Thunderbird < 115.2.

When calling `JS::CheckRegExpSyntax` a Syntax Error could have been set which would end in calling `convertToRuntimeErrorAndClear`. A path in the function could attempt to allocate memory when none is available which would have caused a newly created Out of Memory exception to be mishandled as a Syntax Error. This vulnerability affects Firefox < 117, Firefox ESR < 115.2, and Thunderbird < 115.2.

A website could have obscured the full screen notification by using a URL with a scheme handled by an external program, such as a mailto URL. This could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 116, Firefox ESR < 115.2, and Thunderbird < 115.2.