CVE-2020-26950

critical
Published — · Modified —
CVSS v3
CVSS v2
VIR risk
9.5

Description

In certain circumstances, the MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition. This vulnerability affects Firefox < 82.0.3, Firefox ESR < 78.4.1, and Thunderbird < 78.4.2.

Predictions

Exploit likelihood
20%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2020-26950

vendor Authored 2026-05-27

Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2020-26950.html

vendor Authored 2026-05-27

Vendor advisory: arch — https://security.archlinux.org/ASA-202011-6

OS impact

OSVersionStatusFixed in
arch archfixed82.0.3-1
suse slesaffected
debian debiansidfixed82.0.3-1
debian debianbookwormfixed78.4.1esr-1
debian debianbullseyefixed78.4.1esr-1
debian debianforkyfixed78.4.1esr-1
debian debiantrixiefixed78.4.1esr-1

References

Verify integrity in audit chain (admin only). AS-IS.