CVE-2021-4129

Mozilla developers and community members Julian Hector, Randell Jesup, Gabriele Svelto, Tyson Smith, Christian Holler, and Masayuki Nakano reported memory safety bugs present in Firefox 94. 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 < 95, Firefox ESR < 91.4.0, and Thunderbird < 91.4.0.

Mozilla Firefox is an open-source web browser, designed for standards compliance, performance, and portability.

This update upgrades Firefox to version 91.4.0 ESR.

Security Fix(es):

• Mozilla: Memory safety bugs fixed in Firefox 95 and Firefox ESR 91.4

• Mozilla: URL leakage when navigating while executing asynchronous function (CVE-2021-43536)

• Mozilla: Heap buffer overflow when using structured clone (CVE-2021-43537)

• Mozilla: Missing fullscreen and pointer lock notification when requesting both (CVE-2021-43538)

• Mozilla: GC rooting failure when calling wasm instance methods (CVE-2021-43539)

• Mozilla: External protocol handler parameters were unescaped (CVE-2021-43541)

• Mozilla: XMLHttpRequest error codes could have leaked the existence of an external protocol handler (CVE-2021-43542)

• Mozilla: Bypass of CSP sandbox directive when embedding (CVE-2021-43543)

• Mozilla: Denial of Service when using the Location API in a loop (CVE-2021-43545)

• Mozilla: Cursor spoofing could overlay user interface when native cursor is zoomed (CVE-2021-43546)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Mozilla Thunderbird is a standalone mail and newsgroup client.

This update upgrades Thunderbird to version 91.4.0.

Security Fix(es):

• Mozilla: Memory safety bugs fixed in Firefox 95 and Firefox ESR 91.4 (BZ#2030116)

• Mozilla: URL leakage when navigating while executing asynchronous function (CVE-2021-43536)

• Mozilla: Heap buffer overflow when using structured clone (CVE-2021-43537)

• Mozilla: Missing fullscreen and pointer lock notification when requesting both (CVE-2021-43538)

• Mozilla: GC rooting failure when calling wasm instance methods (CVE-2021-43539)

• Mozilla: External protocol handler parameters were unescaped (CVE-2021-43541)

• Mozilla: XMLHttpRequest error codes could have leaked the existence of an external protocol handler (CVE-2021-43542)

• Mozilla: Bypass of CSP sandbox directive when embedding (CVE-2021-43543)

• Mozilla: JavaScript unexpectedly enabled for the composition area (CVE-2021-43528)

• Mozilla: Denial of Service when using the Location API in a loop (CVE-2021-43545)

• Mozilla: Cursor spoofing could overlay user interface when native cursor is zoomed (CVE-2021-43546)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Mozilla developers and community members Julian Hector, Randell Jesup, Gabriele Svelto, Tyson Smith, Christian Holler, and Masayuki Nakano reported memory safety bugs present in Firefox 94. 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 < 95, Firefox ESR < 91.4.0, and Thunderbird < 91.4.0.

Under certain circumstances, asynchronous functions could have caused a navigation to fail but expose the target URL (CVE-2021-43536).

An incorrect type conversion of sizes from 64bit to 32bit integers allowed an attacker to corrupt memory leading to a potentially exploitable crash due to a heap buffer overflow when using structured clone (CVE-2021-43537).

By misusing a race in our notification code, an attacker could have forcefully hidden the notification for pages that had received both full screen and pointer lock access, which could have been used for spoofing attacks (CVE-2021-43538).

Failure to correctly record the location of live pointers across wasm instance calls resulted in a GC occurring within the call not tracing those live pointers. This could have led to a use-after-free causing a potentially exploitable crash (CVE-2021-43539).

When invoking protocol handlers for external protocols, a supplied parameter URL containing spaces was not properly escaped (CVE-2021-43541).

Using XMLHttpRequest, an attacker could have identified installed applications by probing error messages for loading external protocols (CVE-2021-43542).

Documents loaded with the CSP sandbox directive could have escaped the sandbox's script restriction by embedding additional content (CVE-2021-43543).

Using the Location API in a loop could have caused severe application hangs and crashes (CVE-2021-43545).

It was possible to recreate previous cursor spoofing attacks against users with a zoomed native cursor (CVE-2021-43546).

Mozilla developers and community members Julian Hector, Randell Jesup, Gabriele Svelto, Tyson Smith, Christian Holler, and Masayuki Nakano reported memory safety bugs present in Firefox ESR 91.3. 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 (CVE-2021-4129).

Thunderbird unexpectedly enabled JavaScript in the composition area. The JavaScript execution context was limited to this area and did not receive chrome-level privileges, but could be used as a stepping stone to further an attack with other vulnerabilities (CVE-2021-43528).

Under certain circumstances, asynchronous functions could have caused a navigation to fail but expose the target URL (CVE-2021-43536).

An incorrect type conversion of sizes from 64bit to 32bit integers allowed an attacker to corrupt memory leading to a potentially exploitable crash due to a heap buffer overflow when using structured clone (CVE-2021-43537).

By misusing a race in our notification code, an attacker could have forcefully hidden the notification for pages that had received both full screen and pointer lock access, which could have been used for spoofing attacks (CVE-2021-43538).

Failure to correctly record the location of live pointers across wasm instance calls resulted in a GC occurring within the call not tracing those live
pointers. This could have led to a use-after-free causing a potentially
exploitable crash (CVE-2021-43539).

When invoking protocol handlers for external protocols, a supplied parameter URL containing spaces was not properly escaped (CVE-2021-43541).

Using XMLHttpRequest, an attacker could have identified installed applications by probing error messages for loading external protocols (CVE-2021-43542).

Documents loaded with the CSP sandbox directive could have escaped the sandbox's script restriction by embedding additional content (CVE-2021-43543).

Using the Location API in a loop could have caused severe application hangs and crashes (CVE-2021-43545).

It was possible to recreate previous cursor spoofing attacks against users with a zoomed native cursor (CVE-2021-43546).

Mozilla developers and community members Julian Hector, Randell Jesup, Gabriele Svelto, Tyson Smith, Christian Holler, and Masayuki Nakano reported memory safety bugs present in Thunderbird 91.3. 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 (CVE-2021-4129).

Multiple security issues were discovered in Thunderbird. If a user were tricked into opening a specially crafted website in a browsing context, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information, trick a user into accepting unwanted permissions, conduct header splitting attacks, conduct spoofing attacks, bypass security restrictions, confuse the user, or execute arbitrary code. (CVE-2021-4129, CVE-2021-4140, CVE-2021-29981, CVE-2021-29982, CVE-2021-29987, CVE-2021-29991, CVE-2021-38495, CVE-2021-38496, CVE-2021-38497, CVE-2021-38498, CVE-2021-38500, CVE-2021-38501, CVE-2021-38503, CVE-2021-38504, CVE-2021-38506, CVE-2021-38507, CVE-2021-38508, CVE-2021-38509, CVE-2021-43534, CVE-2021-43535, CVE-2021-43536, CVE-2021-43537, CVE-2021-43538, CVE-2021-43539, CVE-2021-43541, CVE-2021-43542, CVE-2021-43543, CVE-2021-43545, CVE-2021-43656, CVE-2022-22737, CVE-2022-22738, CVE-2022-22739, CVE-2022-22740, CVE-2022-22741, CVE-2022-22742, CVE-2022-22743, CVE-2022-22745, CVE-2022-22747, CVE-2022-22748, CVE-2022-22751)

It was discovered that Thunderbird ignored the configuration to require STARTTLS for an SMTP connection. A person-in-the-middle could potentially exploit this to perform a downgrade attack in order to intercept messages or take control of a session. (CVE-2021-38502)

It was discovered that JavaScript was unexpectedly enabled in the composition area. An attacker could potentially exploit this in combination with another vulnerability, with unspecified impacts. (CVE-2021-43528)

A buffer overflow was discovered in the Matrix chat library bundled with Thunderbird. An attacker could potentially exploit this to cause a denial of service, or execute arbitrary code. (CVE-2021-44538)

It was discovered that Thunderbird's OpenPGP integration only considered the inner signed message when checking signature validity in a message that contains an additional outer MIME layer. An attacker could potentially exploit this to trick the user into thinking that a message has a valid signature. (CVE-2021-4126)