CVE-2022-26485

KEVMozilla Firefox Use-After-Free Vulnerability

Description

Mozilla Firefox contains a use-after-free vulnerability in XSLT parameter processing which can be exploited to perform arbitrary code execution.

Removing an XSLT parameter during processing could have lead to an exploitable use-after-free. We have had reports of attacks in the wild abusing this flaw. This vulnerability affects Firefox < 97.0.2, Firefox ESR < 91.6.1, Firefox for Android < 97.3.0, Thunderbird < 91.6.2, and Focus < 97.3.0.

CVSS 3.1 vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

PublishedDec 22, 2022

Last modifiedAug 19, 2026

Added to KEVMar 7, 2022

Remediation dueMar 21, 2022

References

bugzilla.mozilla.org/show_bug.cgi?id=1758062ExploitIssue Tracking
mozilla.org/security/advisories/mfsa2022-09/Vendor Advisory
cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2022-26485US Government Resource

0 recent articles mention this CVE

Risk assessment · High

Actively exploited. Patch immediately.

Exploitation: Confirmed in the wild (CISA KEV)
Federal remediation deadline: Overdue by 1680 days
CVSS: 8.8 HIGH
EPSS (30-day exploit probability): 14.3% · top 3% of all CVEs
Weakness: CWE-416
Attack vector: Network, remotely reachable

Recommended actions

1.Apply updates per vendor instructions.
2.Treat as emergency change: patch or isolate internet-facing instances first.
3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.

Assessment is derived automatically from the live signals above; verify against your own asset inventory.