CVE-2026-4711

EUVD-2026-14837
Use-after-free in the Widget: Cocoa component. This vulnerability affects Firefox < 149, Firefox ESR < 140.9, Thunderbird < 149, and Thunderbird < 140.9.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
9.8 CRITICAL
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA-ADPADP
9.8 CRITICAL
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Affected Products (NVD)
VendorProductVersion
mozillafirefox_esr
𝑥
< 140.9.0
mozillafirefox
𝑥
< 149.0
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
firefox
sid
148.0.2-1
fixed
firefox-esr
bookworm
128.14.0esr-1~deb12u1
fixed
bookworm (security)
140.9.0esr-1~deb12u1
fixed
bullseye
115.14.0esr-1~deb11u1
fixed
bullseye (security)
140.8.0esr-1~deb11u1
fixed
forky
140.8.0esr-1
fixed
sid
140.9.0esr-1
fixed
trixie
140.8.0esr-1~deb13u1
fixed
trixie (security)
140.9.0esr-1~deb13u1
fixed
thunderbird
bookworm
1:140.6.0esr-1~deb12u1
fixed
bookworm (security)
1:140.8.0esr-1~deb12u1
fixed
bullseye
1:115.12.0-1~deb11u1
fixed
bullseye (security)
1:140.9.0esr-1~deb11u1
fixed
forky
1:140.8.0esr-1
fixed
sid
1:140.9.0esr-1
fixed
trixie
1:140.8.0esr-1~deb13u1
fixed
trixie (security)
1:140.8.0esr-1~deb13u1
fixed
Common Weakness Enumeration
References
https://bugzilla.mozilla.org/show_bug.cgi?id=2017002
https://www.mozilla.org/security/advisories/mfsa2026-20/
https://www.mozilla.org/security/advisories/mfsa2026-22/
https://www.mozilla.org/security/advisories/mfsa2026-23/
https://www.mozilla.org/security/advisories/mfsa2026-24/