VulnerabilityModified
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.
HIGH 8.8EPSS 1.11%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.11%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- 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
- 1.11% probability · 64th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- mozilla/firefox · mozilla/firefox esr · mozilla/thunderbird · debian/debian linux
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1667102Issue Tracking, Permissions Required, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlMailing List, Third Party Advisory
- https://www.debian.org/security/2021/dsa-5026Third Party Advisory
- https://www.debian.org/security/2022/dsa-5034Issue Tracking, Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-43/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-49/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-50/Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1667102Issue Tracking, Permissions Required, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlMailing List, Third Party Advisory
- https://www.debian.org/security/2021/dsa-5026Third Party Advisory
- https://www.debian.org/security/2022/dsa-5034Issue Tracking, Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-43/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-49/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-50/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.