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 affects Firefox ESR < 78.9 and Firefox < 87.

Proxy functionality built into Hubs Cloud’s Reticulum software allowed access to internal URLs, including the metadata service. This vulnerability affects Hubs Cloud < mozillareality/reticulum/1.0.1/20210428201255.

Mozilla: Universal Cross-Site Scripting

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. Further details are being temporarily withheld to allow users an opportunity to update.*. This vulnerability affects Firefox < 88.0.1 and Firefox for Android < 88.1.3.

Mozilla: Race condition in Web Render Components

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.

Mozilla: Thunderbird Maintenance Service could have been started or stopped by domain users

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 exposed attack surface in the maintenance service. *Note: This issue only affected Windows operating systems older than Win 10 build 1709. Other operating systems are unaffected.*. This vulnerability affects Thunderbird < 78.10.1, Firefox < 87, and Firefox ESR < 78.10.1.

Mozilla: Logic issue potentially leaves key material unlocked

Thunderbird unprotects a secret OpenPGP key prior to using it for a decryption, signing or key import task. If the task runs into a failure, the secret key may remain in memory in its unprotected state. This vulnerability affects Thunderbird < 78.8.1.

Mozilla: Thunderbird might execute an alternative OTR library

When loading the shared library that provides the OTR protocol implementation, Thunderbird will initially attempt to open it using a filename that isn't distributed by Thunderbird. If a computer has already been infected with a malicious library of the alternative filename, and the malicious library has been copied to a directory that is contained in the search path for executable libraries, then Thunderbird will load the incorrect library. This vulnerability affects Thunderbird < 78.9.1.

Mozilla: Race condition when reading from disk while verifying signatures

Signatures are written to disk before and read during verification, which might be subject to a race condition when a malicious local process or user is replacing the file. This vulnerability affects Thunderbird < 78.10.

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.

Mozilla: Port blocking could be bypassed

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.

Mozilla: Incorrect size computation in WebAssembly JIT could lead to null-reads

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.

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 affects Firefox < 88.

Mozilla: Arbitrary FTP command execution on FTP servers using an encoded URL

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.

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.

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 &lt;input type="file"&gt;) this could have led to an attack where a user was confused about the origin of the webpage and potentially disclosed information they did not intend to. This vulnerability affects Firefox < 88.

Mozilla: Blob URLs may have been granted additional privileges

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.

Mozilla: Secure Lock icon could have been spoofed

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.

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.

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.

Mozilla: Use-after-free in Responsive Design Mode

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.