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[MFSA-2021-50] Security Vulnerabilities fixed in Thunderbird 91.3

Severity High
Affected Packages 1
Fixed Packages 1
CVEs 11
Info Packages References Vulnerabilities

In general, these flaws cannot be exploited through email in the Thunderbird product because scripting is disabled when reading mail, but are potentially risks in browser or browser-like contexts.*
This advisory was updated January 17, 2023 to add CVE-2021-43529. This fix was included in the original release of Thunderbird 91.3, but did not appear in the advisory published at that time.

  • CVE-2021-38503: iframe sandbox rules did not apply to XSLT stylesheets (high)
    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-2021-38504: Use-after-free in file picker dialog (high)
    When interacting with an HTML input element's file picker dialog with <code>webkitdirectory</code> set, a use-after-free could have resulted, leading to memory corruption and a potentially exploitable crash.

  • CVE-2021-38505: Windows 10 Cloud Clipboard may have recorded sensitive user data (high)
    Microsoft introduced a new feature in Windows 10 known as Cloud Clipboard which, if enabled, will record data copied to the clipboard to the cloud, and make it available on other computers in certain scenarios. Applications that wish to prevent copied data from being recorded in Cloud History must use specific clipboard formats; and Thunderbird before version 91.3 did not implement them. This could have caused sensitive data to be recorded to a user's Microsoft account.
    This bug only affects Thunderbird for Windows 10+ with Cloud Clipboard enabled. Other operating systems are unaffected.

  • CVE-2021-38506: Thunderbird could be coaxed into going into fullscreen mode without notification or warning (high)
    Through a series of web 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-2021-38507: Opportunistic Encryption in HTTP2 could be used to bypass the Same-Origin-Policy on services hosted on other ports (high)
    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-2021-38508: Permission Prompt could be overlaid, resulting in user confusion and potential spoofing (moderate)
    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-2021-38509: Javascript alert box could have been spoofed onto an arbitrary domain (moderate)
    Due to an unusual sequence of attacker-controlled events, a Javascript <code>alert()</code> dialog with arbitrary (although unstyled) contents could be displayed over top an uncontrolled webpage of the attacker's choosing.

  • CVE-2021-38510: Download Protections were bypassed by .inetloc files on Mac OS (moderate)
    The executable file warning was not presented when downloading .inetloc files, which, due to a flaw in Mac OS, can run commands on a user's computer.
    Note: This issue only affected Mac OS operating systems. Other operating systems are unaffected.

  • CVE-2021-43529: Memory corruption when processing S/MIME messages (critical)
    Thunderbird versions prior to 91.3.0 are vulnerable to the heap overflow described in CVE-2021-43527 when processing S/MIME messages. Thunderbird versions 91.3.0 and later will not call the vulnerable code when processing S/MIME messages that contain certificates with DER-encoded DSA or RSA-PSS signatures.
    Note: This advisory was added on January 17, 2023 after discovering it was inadvertently left out of the original advisory. The fix was included in the original release of Thunderbird 91.3.

  • CVE-2021-43534: Memory safety bugs fixed in Thunderbird ESR 91.3 (high)
    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-2021-43535: Use-after-free in HTTP2 Session object (high)
    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.

Package Affected Version
pkg:mozilla/Thunderbird < 91.3
Package Fixed Version
pkg:mozilla/Thunderbird = 91.3
ID
MFSA-2021-50
Severity
high
URL
https://www.mozilla.org/en-US/security/advisories/mfsa2021-50
Published
2021-11-03T00:00:00
(2 years ago)
Modified
2021-11-03T00:00:00
(2 years ago)
Other Advisories
Type Package URL Namespace Name / Product Version Distribution / Platform Arch Patch / Fix
Affected pkg:mozilla/Thunderbird Thunderbird < 91.3
Fixed pkg:mozilla/Thunderbird Thunderbird = 91.3
# CVE Description CVSS EPSS EPSS Trend (30 days) Affected Products Weaknesses Security Advisories Exploits PoC Pubblication Date Modification Date
# CVE Description CVSS EPSS EPSS Trend (30 days) Affected Products Weaknesses Security Advisories PoC Pubblication Date Modification Date