CVE-2026-92056: mozilla firefox Use After Free
CVSS: 8.8v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-92056DEBIAN-CVE-2026-92056
Published 15-09-2026Last modified 20-09-2026
Vulnerability summary
CVE-2026-92056 is a high (CVSS 8.8) Use After Free vulnerability in mozilla firefox. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 13.2% of scored vulnerabilities.
CVSS score
8.8/10
010
High · v3.1 (CVE.org)EPSS score
0.23%
0%100%
Low · -0.01 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 10 · Related 8Timeline
- 15-09-2026PublishedVulnerability first disclosed.
- 20-09-2026Last modifiedVulnerability information updated.
Description
Use-after-free in the Graphics: Text component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.
CVSS metrics
4 scores · 4 sources · 1 versionHigh 8.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HSourcesAll 4 agree
- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- NVDNIST8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.23%
Chance of exploitation in the next 30 days
Percentile
13%
Versus all other CVEs
30-day change
-0.01 pp
From 0.25% on 20-09-2026
20-09-202620-10-2026
EPSS score0.23%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu8 products
- mozjs102All versions (No fix recorded)
- mozjs115All versions (No fix recorded)
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
Mozilla2 products
- firefox< 153.3.0 | ≥ 154.0.0, < 156.0.0
- thunderbird< 153.3.0 | ≥ 154.0, < 156.0
Debian1 product
- thunderbird< 1:153.3.0esr-1
3 vendors · 11 products
References
9 links- bugzilla.mozilla.org/show_bug.cgi?id=2065346Permissions Required
- www.mozilla.org/security/advisories/mfsa2026-90/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-93/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-94/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-96/Vendor Advisory