High severity · published May 19, 2026
CVE-2026-8946
Incorrect boundary conditions in the Audio/Video: Web Codecs component
7.5
CVSS
0.6%
EPSS
No
On KEV
Description
Incorrect boundary conditions in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 46% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
Firefox · Mozilla
before 115.36.0; before 151.0.0; 140.0 before 140.11.0 · source: NVD
TH
Thunderbird · Mozilla
before 140.11 · source: NVD
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 10.0 Extended Update Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 6 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 7 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 7 Extended Lifecycle Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On · Red Hat
All versions, or not specified · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-8946
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-8946
Permissions Required
https://bugzilla.mozilla.org/show_bug.cgi?id=2029070
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-46/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-47/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-48/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-50/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-51/
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