Mozilla Firefox And Thunderbird Type Confusion Vulnerability

[ Why it matters ]Priority signals

• Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2021-11-03
• EPSS: 46% chance of exploitation in the next 30 days (higher than 99% of CVEs)

[ Description ]Official description

Incorrect alias information in IonMonkey JIT compiler for setting array elements could lead to a type confusion. We are aware of targeted attacks in the wild abusing this flaw. This vulnerability affects Firefox ESR < 68.4.1, Thunderbird < 68.4.1, and Firefox < 72.0.1.

CISA: Mozilla Firefox and Thunderbird contain a type confusion vulnerability due to incorrect alias information in the IonMonkey JIT compiler when setting array elements.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 3 May 2022): Apply updates per vendor instructions.

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ References ]References

• packetstormsecurity.com/files/162568/Firefox-72-IonMonkey-JIT-Type-Confusion.htmlExploitThird Party AdvisoryVDB Entry
• bugzilla.mozilla.org/show_bug.cgiIssue Tracking
• security.gentoo.org/glsa/202003-02Third Party Advisory
• usn.ubuntu.com/4335-1Third Party Advisory
• www.mozilla.org/security/advisories/mfsa2020-03Vendor Advisory
• www.mozilla.org/security/advisories/mfsa2020-04Vendor Advisory
• www.cisa.gov/known-exploited-vulnerabilities-catalogUS Government Resource