CVE-2026-0878

EUVD-2026-2340
Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
8 HIGH
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
CISA-ADPADP
8 HIGH
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 9%
Affected Products (NVD)
VendorProductVersion
mozillafirefox
𝑥
< 140.7.0
mozillafirefox
𝑥
< 147.0
mozillathunderbird
𝑥
< 140.7.0
mozillathunderbird
𝑥
< 147.0
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
firefox
sid
148.0-1
fixed
firefox-esr
bookworm
vulnerable
bookworm (security)
140.8.0esr-1~deb12u1
fixed
bullseye
vulnerable
bullseye (security)
140.7.0esr-1~deb11u1
fixed
forky
140.7.0esr-1
fixed
sid
140.8.0esr-1
fixed
trixie
vulnerable
trixie (security)
140.8.0esr-1~deb13u1
fixed
thunderbird
bookworm
vulnerable
bookworm (security)
1:140.7.1esr-1~deb12u1
fixed
bullseye
vulnerable
bullseye (security)
1:140.7.1esr-1~deb11u1
fixed
forky
1:140.7.1esr-1
fixed
sid
1:140.8.0esr-1
fixed
trixie
vulnerable
trixie (security)
1:140.7.1esr-1~deb13u1
fixed
Common Weakness Enumeration
References
https://bugzilla.mozilla.org/show_bug.cgi?id=2003989
https://www.mozilla.org/security/advisories/mfsa2026-01/
https://www.mozilla.org/security/advisories/mfsa2026-03/
https://www.mozilla.org/security/advisories/mfsa2026-04/
https://www.mozilla.org/security/advisories/mfsa2026-05/