Critical severity · published Jan 13, 2026
CVE-2026-0879
Sandbox escape due to incorrect boundary conditions in the Graphics component
9.8
CVSS
0.5%
EPSS
No
On KEV
Description
Sandbox escape due to incorrect boundary conditions in the Graphics component. This vulnerability was fixed in Firefox 147, Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
Firefox · Mozilla
before 115.32.0; before 147.0; 128.0 before 140.7.0 · source: NVD
TH
Thunderbird · Mozilla
before 140.7.0; before 147.0 · 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 8.2 Advanced Update Support · 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
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-0879
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-0879
Permissions Required
https://bugzilla.mozilla.org/show_bug.cgi?id=2004602
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-01/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-02/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-03/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-04/
Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-05/
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