CVE-2026-8091: mozilla firefox
CVSS: 9.8v3.1CriticalModified
AliasesUBUNTU-CVE-2026-8091DEBIAN-CVE-2026-8091CGA-67px-557v-8jr4CGA-r993-vmjj-prgxCGA-4m3m-mjfv-vc67CGA-f8q8-24x5-r5qj
Published 07-05-2026Last modified 11-08-2026
Vulnerability summary
CVE-2026-8091 is a critical (CVSS 9.8) vulnerability in mozilla firefox. EPSS estimates a 0.60% chance of exploitation in the next 30 days, higher than 47.7% of scored vulnerabilities.
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)EPSS score
0.60%
0%100%
Low · +0.13 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 23 · Related 2OPENSUSE-SU-2026:10720-1RHSA-2026:19153RHSA-2026:19157RHSA-2026:19348RHSA-2026:19370RHSA-2026:19588RHSA-2026:20586RHSA-2026:21743RHSA-2026:22324RHSA-2026:22408RHSA-2026:22409RHSA-2026:22410RHSA-2026:22708RHSA-2026:22712RHSA-2026:22847RHSA-2026:24345RHSA-2026:24717RHSA-2026:24718RHSA-2026:24719RHSA-2026:24721RHSA-2026:24844RHSA-2026:24846RHSA-2026:25014CGA-92CR-4QC8-W5PJ
Timeline
- 07-05-2026PublishedVulnerability first disclosed.
- 11-08-2026Last modifiedVulnerability information updated.
Description
Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 150, Thunderbird 150, Firefox ESR 140.10.1, Thunderbird 140.10.1, and Firefox ESR 115.35.2.
CVSS metrics
4 scores · 4 sources · 1 versionCritical 9.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSources4 sources · 7.5–9.8
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:HDiffers
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVDNIST9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.60%
Chance of exploitation in the next 30 days
Percentile
48%
Versus all other CVEs
30-day change
+0.13 pp
From 0.47% on 21-09-2026
21-09-202621-10-2026
EPSS score0.60%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-754Improper Check for Unusual or Exceptional ConditionsThe product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.
- CWE-805Buffer Access with Incorrect Length ValueThe product uses a sequential operation to read or write a buffer, but it uses an incorrect length value that causes it to access memory that is outside of the bounds of the buffer.
Affected 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)
Chainguard2 products
- firefox< 140.10.1-r0
- firefox-esr< 140.10.1-r0
Debian2 products
- firefox-esr< 140.10.1esr-1~deb12u1 | < 140.10.1esr-1~deb13u1 | < 140.10.1esr-1
- thunderbird< 1:140.10.1esr-1~deb12u1 | < 1:140.10.1esr-1~deb13u1 | < 1:140.10.1esr-1
Mozilla2 products
- firefox< 115.35.2 | ≥ 140.0, < 140.10.1
- thunderbird≥ 140.0, < 140.10.1
Wolfi1 product
- firefox< 140.10.1-r0
5 vendors · 15 products
References
37 links- bugzilla.mozilla.org/show_bug.cgi?id=2029301Permissions Required
- www.mozilla.org/security/advisories/mfsa2026-30/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-33/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-36/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-39/Vendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-42/Vendor Advisory
