CVE-2021-43535

A use-after-free could have occured when an HTTP2 session object was released on a different thread, leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 93, Thunderbird < 91.3, and Firefox ESR < 91.3.

Mozilla Firefox is a standalone web browser, designed for standards compliance and performance. Its functionality can be enhanced via a plethora of extensions.

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

Security Fix(es):

Mozilla developers reported memory safety bugs present in Firefox for Android 79. 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 < 80, Firefox ESR < 78.2, Thunderbird < 78.2, and Firefox for Android < 80.(CVE-2020-15670)

Mozilla developers reported memory safety bugs present in Firefox 80 and Firefox ESR 78.2. 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 < 81, Thunderbird < 78.3, and Firefox ESR < 78.3.(CVE-2020-15673)

Mozilla developers reported memory safety bugs present in Firefox 80. 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 < 81.(CVE-2020-15674)

When processing surfaces, the lifetime may outlive a persistent buffer leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 81.(CVE-2020-15675)

If a valid external protocol handler was referenced in an image tag, the resulting broken image size could be distinguished from a broken image size of a non-existent protocol handler. This allowed an attacker to successfully probe whether an external protocol handler was registered. This vulnerability affects Firefox < 82.(CVE-2020-15680)

When multiple WASM threads had a reference to a module, and were looking up exported functions, one WASM thread could have overwritten another's entry in a shared stub table, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 82.(CVE-2020-15681)

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.(CVE-2020-15682)

Mozilla developers and community members reported memory safety bugs present in Firefox 81 and Firefox ESR 78.3. 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. This vulnerability affects Firefox ESR < 78.4, Firefox < 82, and Thunderbird < 78.4.(CVE-2020-15683)

Mozilla developers reported memory safety bugs present in Firefox 81. 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 < 82.(CVE-2020-15684)

Side-channel information leakage in graphics in Google Chrome prior to 87.0.4280.66 allowed a remote attacker to leak cross-origin data via a crafted HTML page.(CVE-2020-16012)

Use after free in WebRTC in Google Chrome prior to 88.0.4324.96 allowed a remote attacker to potentially exploit heap corruption via a crafted SCTP packet.(CVE-2020-16044)

In certain circumstances, the MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition. This vulnerability affects Firefox < 82.0.3, Firefox ESR < 78.4.1, and Thunderbird < 78.4.2.(CVE-2020-26950)

(CVE-2020-26951)

(CVE-2020-26953)

…

Mozilla Firefox is a standalone web browser, designed for standards compliance and performance. Its functionality can be enhanced via a plethora of extensions.

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

Security Fix(es):

Mozilla developers reported memory safety bugs present in Firefox for Android 79. 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 < 80, Firefox ESR < 78.2, Thunderbird < 78.2, and Firefox for Android < 80.(CVE-2020-15670)

Mozilla developers reported memory safety bugs present in Firefox 80 and Firefox ESR 78.2. 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 < 81, Thunderbird < 78.3, and Firefox ESR < 78.3.(CVE-2020-15673)

Mozilla developers reported memory safety bugs present in Firefox 80. 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 < 81.(CVE-2020-15674)

When processing surfaces, the lifetime may outlive a persistent buffer leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 81.(CVE-2020-15675)

If a valid external protocol handler was referenced in an image tag, the resulting broken image size could be distinguished from a broken image size of a non-existent protocol handler. This allowed an attacker to successfully probe whether an external protocol handler was registered. This vulnerability affects Firefox < 82.(CVE-2020-15680)

When multiple WASM threads had a reference to a module, and were looking up exported functions, one WASM thread could have overwritten another's entry in a shared stub table, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 82.(CVE-2020-15681)

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.(CVE-2020-15682)

Mozilla developers and community members reported memory safety bugs present in Firefox 81 and Firefox ESR 78.3. 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. This vulnerability affects Firefox ESR < 78.4, Firefox < 82, and Thunderbird < 78.4.(CVE-2020-15683)

Mozilla developers reported memory safety bugs present in Firefox 81. 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 < 82.(CVE-2020-15684)

Side-channel information leakage in graphics in Google Chrome prior to 87.0.4280.66 allowed a remote attacker to leak cross-origin data via a crafted HTML page.(CVE-2020-16012)

Use after free in WebRTC in Google Chrome prior to 88.0.4324.96 allowed a remote attacker to potentially exploit heap corruption via a crafted SCTP packet.(CVE-2020-16044)

In certain circumstances, the MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition. This vulnerability affects Firefox < 82.0.3, Firefox ESR < 78.4.1, and Thunderbird < 78.4.2.(CVE-2020-26950)

(CVE-2020-26951)

(CVE-2020-26953)

…

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

This update upgrades Firefox to version 91.3.0 ESR.

Security Fix(es):

• Mozilla: Use-after-free in HTTP2 Session object

• Mozilla: Memory safety bugs fixed in Firefox 94 and Firefox ESR 91.3

• Mozilla: iframe sandbox rules did not apply to XSLT stylesheets (CVE-2021-38503)

• Mozilla: Use-after-free in file picker dialog (CVE-2021-38504)

• Mozilla: Firefox could be coaxed into going into fullscreen mode without notification or warning (CVE-2021-38506)

• Mozilla: Opportunistic Encryption in HTTP2 could be used to bypass the Same-Origin-Policy on services hosted on other ports (CVE-2021-38507)

• Mozilla: Permission Prompt could be overlaid, resulting in user confusion and potential spoofing (CVE-2021-38508)

• Mozilla: Javascript alert box could have been spoofed onto an arbitrary domain (CVE-2021-38509)

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 91.3.0.

Security Fix(es):

• Mozilla: Use-after-free in HTTP2 Session object

• Mozilla: Memory safety bugs fixed in Firefox 94 and Firefox ESR 91.3

• Mozilla: iframe sandbox rules did not apply to XSLT stylesheets (CVE-2021-38503)

• Mozilla: Use-after-free in file picker dialog (CVE-2021-38504)

• Mozilla: Firefox could be coaxed into going into fullscreen mode without notification or warning (CVE-2021-38506)

• Mozilla: Opportunistic Encryption in HTTP2 could be used to bypass the Same-Origin-Policy on services hosted on other ports (CVE-2021-38507)

• Mozilla: Permission Prompt could be overlaid, resulting in user confusion and potential spoofing (CVE-2021-38508)

• Mozilla: Javascript alert box could have been spoofed onto an arbitrary domain (CVE-2021-38509)

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.

A use-after-free could have occured when an HTTP2 session object was released on a different thread, leading to memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 93, Thunderbird < 91.3, and Firefox ESR < 91.3.

The iframe sandbox rules were not correctly applied to XSLT stylesheets, allowing an iframe to bypass restrictions such as executing scripts or navigating the top-level frame (CVE-2021-38503).

When interacting with an HTML input element's file picker dialog with webkitdirectory set, a use-after-free could have resulted, leading to memory corruption and a potentially exploitable crash (CVE-2021-38504).

Through a series of navigations, Firefox could have entered fullscreen mode without notification or warning to the user. This could lead to spoofing attacks on the browser UI including phishing (CVE-2021-38506).

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 (CVE-2021-38507).

A use-after-free could have occured when an HTTP2 session object was released on a different thread, leading to memory corruption and a potentially exploitable crash (CVE-2021-43535).

By displaying a form validity message in the correct location at the same time as a permission prompt (such as for geolocation), the validity message could have obscured the prompt, resulting in the user potentially being tricked into granting the permission (CVE-2021-38508).

Due to an unusual sequence of attacker-controlled events, a Javascript alert() dialog with arbitrary (although unstyled) contents could be displayed over top an uncontrolled webpage of the attacker's choosing (CVE-2021-38509).

Mozilla developers and community members Christian Holler, Valentin Gosu, and Andrew McCreight reported memory safety bugs present in Firefox ESR 91.2. 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-2021-43534).

Updated thunderbird packages fix security vulnerabilities:

The iframe sandbox rules were not correctly applied to XSLT stylesheets, allowing an iframe to bypass restrictions such as executing scripts or navigating the top-level frame (CVE-2021-38503).

When interacting with an HTML input element's file picker dialog with webkitdirectory set, a use-after-free could have resulted, leading to memory corruption and a potentially exploitable crash (CVE-2021-38504).

Through a series of navigations, Thunderbird could have entered fullscreen mode without notification or warning to the user. This could lead to spoofing attacks on the browser UI including phishing (CVE-2021-38506).

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 (CVE-2021-38507).

A use-after-free could have occured when an HTTP2 session object was released on a different thread, leading to memory corruption and a potentially exploitable crash (CVE-2021-43535).

By displaying a form validity message in the correct location at the same time as a permission prompt (such as for geolocation), the validity message could have obscured the prompt, resulting in the user potentially being tricked into granting the permission (CVE-2021-38508).

Due to an unusual sequence of attacker-controlled events, a Javascript alert() dialog with arbitrary (although unstyled) contents could be displayed over top an uncontrolled webpage of the attacker's choosing (CVE-2021-38509).

Mozilla developers and community members Christian Holler, Valentin Gosu, and Andrew McCreight reported memory safety bugs present in Thunderbird 91.2. 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-2021-43534).

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)