VulnerabilityModified
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.
HIGH 8.8EPSS 1.19%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.19%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 1.19% probability · 66th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-843
- Affected
- mozilla/firefox · mozilla/firefox esr · mozilla/thunderbird
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1684020Issue Tracking, Permissions Required, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-03/Release Notes, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-04/Release Notes, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-05/Release Notes, Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1684020Issue Tracking, Permissions Required, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-03/Release Notes, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-04/Release Notes, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-05/Release Notes, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.