by Kastro
Paper/Archive/CVE-2026-117920

CVE-2026-117920

Mozilla Firefox — Use-after-free in the DOM: HTML Parser component

EPSS 0.2%CVSS 9.6
critical.is priorityof 100
30
CVSS 9.6 (ADP)9.6 / 10 × 3028.8Not in CISA KEV+300.0EPSS percentile 7.8.078 × 201.6No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

Use-after-free in the DOM: HTML Parser component. This vulnerability was fixed in Firefox 159, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.

Affected

ProductAffectedFixed inSource
Firefoxsee advisory153.6CNA
Thunderbirdsee advisory153.6CNA

Scores by source

CISA ADP9.6CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

refbugzilla.mozilla.org/show_bug.cgi?id=2079681refmozilla.org/security/advisories/mfsa2026-118refmozilla.org/security/advisories/mfsa2026-120refmozilla.org/security/advisories/mfsa2026-121refmozilla.org/security/advisories/mfsa2026-122