Vulnerability in Mozilla Firefox
CVE-2021-23954
Using the new logical assignment operators in a JavaScript switch statement could have caused a type confusion, leading to a memory corruption and a potentially exploitable crash. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.012 (66.8th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 67th percentile — 66.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.011 · newest: 0.012 · change: +0.001
Affected products
- Mozilla Firefox — versions < 85
- Mozilla Firefox Esr — versions < 78.7
- Mozilla Firefox Esr
- Mozilla Thunderbird — versions < 78.7
Weakness classification (CWE)
References
- www.mozilla.org/security/advisories/mfsa2021-03/ (Release Notes, Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2021-04/ (Release Notes, Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2021-05/ (Release Notes, Vendor Advisory)
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking, Vendor Advisory)
Frequently asked questions
- What is CVE-2021-23954?
- CVE-2021-23954 is a high-severity vulnerability in Mozilla Firefox, classified under Access of Resource Using Incompatible Type (Type Confusion). CVSS score: 8.8/10. Published 2021-02-26.
- How severe is CVE-2021-23954?
- High severity. CVSS v3 base score is 8.8 out of 10.