Firefox Security Vulnerabilities

CVE-2021-23978

Mozilla developers reported memory safety bugs present in Firefox 85 and Firefox ESR 78.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 86, Thunde...

CVE-2021-23979

Mozilla developers reported memory safety bugs present in Firefox 85. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 86.

CVE-2021-23981

A texture upload of a Pixel Buffer Object could have confused the WebGL code to skip binding the buffer used to unpack it, resulting in memory corruption and a potentially exploitable information leak or crash. This vulnerability affects Firefox ESR < 78.9, Firefox < 87, and Thunderbird < ...

CVE-2021-23982

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 &l...

CVE-2021-23983

By causing a transition on a parent node by removing a CSS rule, an invalid property for a marker could have been applied, resulting in memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 87.

CVE-2021-23984

A malicious extension could have opened a popup window lacking an address bar. The title of the popup lacking an address bar should not be fully controllable, but in this situation was. This could have been used to spoof a website and attempt to trick the user into providing credentials. This vulne...

CVE-2021-23985

If an attacker is able to alter specific about:config values (for example malware running on the user's computer), the Devtools remote debugging feature could have been enabled in a way that was unnoticable to the user. This would have allowed a remote attacker (able to make a direct network connec...

CVE-2021-23986

A malicious extension with the 'search' permission could have installed a new search engine whose favicon referenced a cross-origin URL. The response to this cross-origin request could have been read by the extension, allowing a same-origin policy bypass by the extension, which should not have cros...

CVE-2021-23987

Mozilla developers and community members reported memory safety bugs present in Firefox 86 and Firefox ESR 78.8. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects F...

CVE-2021-23988

Mozilla developers reported memory safety bugs present in Firefox 86. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 87.

CVE-2021-23994

A WebGL framebuffer was not initialized early enough, resulting in memory corruption and an out of bound write. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

CVE-2021-23995

When Responsive Design Mode was enabled, it used references to objects that were previously freed. We presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

CVE-2021-23996

By utilizing 3D CSS in conjunction with Javascript, content could have been rendered outside the webpage's viewport, resulting in a spoofing attack that could have been used for phishing or other attacks on a user. This vulnerability affects Firefox < 88.

CVE-2021-23997

Due to unexpected data type conversions, a use-after-free could have occurred when interacting with the font cache. We presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox < 88.

CVE-2021-23998

Through complicated navigations with new windows, an HTTP page could have inherited a secure lock icon from an HTTPS page. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

CVE-2021-23999

If a Blob URL was loaded through some unusual user interaction, it could have been loaded by the System Principal and granted additional privileges that should not be granted to web content. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

CVE-2021-24000

A race condition with requestPointerLock() and setTimeout() could have resulted in a user interacting with one tab when they believed they were on a separate tab. In conjunction with certain elements (such as <input type="file">) this could have led to an attack where a user was confused abou...

CVE-2021-24001

A compromised content process could have performed session history manipulations it should not have been able to due to testing infrastructure that was not restricted to testing-only configurations. This vulnerability affects Firefox < 88.

CVE-2021-24002

When a user clicked on an FTP URL containing encoded newline characters (%0A and %0D), the newlines would have been interpreted as such and allowed arbitrary commands to be sent to the FTP server. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

CVE-2021-29944

Lack of escaping allowed HTML injection when a webpage was viewed in Reader View. While a Content Security Policy prevents direct code execution, HTML injection is still possible. Note: This issue only affected Firefox for Android. Other operating systems are unaffected. . This vulnerability affect...

CVE-2021-29945

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.

CVE-2021-29946

Ports that were written as an integer overflow above the bounds of a 16-bit integer could have bypassed port blocking restrictions when used in the Alt-Svc header. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.

CVE-2021-29947

Mozilla developers and community members reported memory safety bugs present in Firefox 87. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 88.

CVE-2021-29951

The Mozilla Maintenance Service granted SERVICE_START access to BUILTIN|Users which, in a domain network, grants normal remote users access to start or stop the service. This could be used to prevent the browser update service from operating (if an attacker spammed the 'Stop' command); but also exp...

CVE-2021-29952

When Web Render components were destructed, a race condition could have caused undefined behavior, and we presume that with enough effort may have been exploitable to run arbitrary code. This vulnerability affects Firefox < 88.0.1 and Firefox for Android < 88.1.3.

CVE-2021-29953

A malicious webpage could have forced a Firefox for Android user into executing attacker-controlled JavaScript in the context of another domain, resulting in a Universal Cross-Site Scripting vulnerability. Note: This issue only affected Firefox for Android. Other operating systems are unaffected. F...

CVE-2021-29955

A transient execution vulnerability, named Floating Point Value Injection (FPVI) allowed an attacker to leak arbitrary memory addresses and may have also enabled JIT type confusion attacks. (A related vulnerability, Speculative Code Store Bypass (SCSB), did not affect Firefox.). This vulnerability ...

CVE-2021-29958

When a download was initiated, the client did not check whether it was in normal or private browsing mode, which led to private mode cookies being shared in normal browsing mode. This vulnerability affects Firefox for iOS < 34.

CVE-2021-29959

When a user has already allowed a website to access microphone and camera, disabling camera sharing would not fully prevent the website from re-enabling it without an additional prompt. This was only possible if the website kept recording with the microphone until re-enabling the camera. This vulne...

CVE-2021-29960

Firefox used to cache the last filename used for printing a file. When generating a filename for printing, Firefox usually suggests the web page title. The caching and suggestion techniques combined may have lead to the title of a website visited during private browsing mode being stored on disk. T...

CVE-2021-29961

When styling and rendering an oversized <select> element, Firefox did not apply correct clipping which allowed an attacker to paint over the user interface. This vulnerability affects Firefox < 89.

CVE-2021-29962

Firefox for Android would become unstable and hard-to-recover when a website opened too many popups. This bug only affects Firefox for Android. Other operating systems are unaffected. . This vulnerability affects Firefox < 89.

CVE-2021-29963

Address bar search suggestions in private browsing mode were re-using session data from normal mode. This bug only affects Firefox for Android. Other operating systems are unaffected. . This vulnerability affects Firefox < 89.

CVE-2021-29964

A locally-installed hostile program could send WM_COPYDATA messages that Firefox would process incorrectly, leading to an out-of-bounds read. This bug only affects Firefox on Windows. Other operating systems are unaffected. . This vulnerability affects Thunderbird < 78.11, Firefox < 89, and F...

CVE-2021-29965

A malicious website that causes an HTTP Authentication dialog to be spawned could trick the built-in password manager to suggest passwords for the currently active website instead of the website that triggered the dialog. This bug only affects Firefox for Android. Other operating systems are unaffe...

CVE-2021-29966

Mozilla developers reported memory safety bugs present in Firefox 88. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 89.

CVE-2021-29967

Mozilla developers reported memory safety bugs present in Firefox 88 and Firefox ESR 78.11. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Thunderbird < 78.11...

CVE-2021-29968

When drawing text onto a canvas with WebRender disabled, an out of bounds read could occur. This bug only affects Firefox on Windows. Other operating systems are unaffected. . This vulnerability affects Firefox < 89.0.1.

CVE-2021-29970

A malicious webpage could have triggered a use-after-free, memory corruption, and a potentially exploitable crash. This bug could only be triggered when accessibility was enabled. . This vulnerability affects Thunderbird < 78.12, Firefox ESR < 78.12, and Firefox < 90.

CVE-2021-29971

If a user had granted a permission to a webpage and saved that grant, any webpage running on the same host - irrespective of scheme or port - would be granted that permission. This bug only affects Firefox for Android. Other operating systems are unaffected. . This vulnerability affects Firefox &lt...

CVE-2021-29972

A use-after-free vulnerability was found via testing, and traced to an out-of-date Cairo library. Updating the library resolved the issue, and may have remediated other, unknown security vulnerabilities as well. This vulnerability affects Firefox < 90.

CVE-2021-29973

Password autofill was enabled without user interaction on insecure websites on Firefox for Android. This was corrected to require user interaction with the page before a user's password would be entered by the browser's autofill functionality This bug only affects Firefox for Android. Other operati...

CVE-2021-29974

When network partitioning was enabled, e.g. as a result of Enhanced Tracking Protection settings, a TLS error page would allow the user to override an error on a domain which had specified HTTP Strict Transport Security (which implies that the error should not be override-able.) This issue did not ...

CVE-2021-29975

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 ...

CVE-2021-29976

Mozilla developers reported memory safety bugs present in code shared between Firefox and Thunderbird. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Thunderbird...

CVE-2021-29977

Mozilla developers reported memory safety bugs present in Firefox 89. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 90.

CVE-2021-29980

Uninitialized memory in a canvas object could have caused an incorrect free() leading to memory corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 78.13, Thunderbird < 91, Firefox ESR < 78.13, and Firefox < 91.

CVE-2021-29981

An issue present in lowering/register allocation could have led to obscure but deterministic register confusion failures in JITted code that would lead to a potentially exploitable crash. This vulnerability affects Firefox < 91 and Thunderbird < 91.

CVE-2021-29982

Due to incorrect JIT optimization, we incorrectly interpreted data from the wrong type of object, resulting in the potential leak of a single bit of memory. This vulnerability affects Firefox < 91 and Thunderbird < 91.

CVE-2021-29983

Firefox for Android could get stuck in fullscreen mode and not exit it even after normal interactions that should cause it to exit. Note: This issue only affected Firefox for Android. Other operating systems are unaffected. . This vulnerability affects Firefox < 91.