CVE-2021-43535
8.8
HIGH
CVSS 3.1
EPSS 1.2%
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.
How to fix CVE-2021-43535
To remediate CVE-2021-43535, upgrade the affected package to a fixed version below.
- Debian/firefox-esr—upgrade to 91.4.1esr-1~deb11u1 or later
- —upgrade to 1:91.4.1-1~deb11u1 or later
Is CVE-2021-43535 being exploited?
Low — EPSS is 1.2%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 91.4.1esr-1~deb11u1
- from 0, < 1:91.4.1-1~deb11u1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |