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Vulnerability · Published May 19, 2026 · Assigned by mozilla

CVE-2026-8947Use-after-free in the DOM: Bindings (WebIDL) component

High 7.3

In plain English

A high-severity use-after-free in Firefox from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.3High
Exploit odds (30 days)0.4%top 64.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Use-after-free in the DOM: Bindings (WebIDL) component. This vulnerability was fixed in Firefox 151, Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10firefox140.11.0-1.el10_2ALSA-2026:21380
AlmaLinux:8firefox140.11.0-1.el8_10.alma.1ALSA-2026:21382
AlmaLinux:9firefox140.11.0-1.el9_8.alma.1ALSA-2026:21378
AlmaLinux:9firefox-x11140.11.0-1.el9_8.alma.1ALSA-2026:21378
AlmaLinux:10thunderbird140.11.0-1.el10_2.alma.1ALSA-2026:22325
AlmaLinux:8thunderbird140.11.0-1.el8_10.alma.1ALSA-2026:22643
AlmaLinux:9thunderbird140.11.0-1.el9_8.alma.1ALSA-2026:21381
Debian:12firefox-esr140.11.0esr-1~deb12u1DEBIAN-CVE-2026-8947
Debian:13firefox-esr140.11.0esr-1~deb13u1DEBIAN-CVE-2026-8947
Debian:14firefox-esr140.11.0esr-1DEBIAN-CVE-2026-8947
Debian:12thunderbird1:140.11.0esr-1~deb12u1DEBIAN-CVE-2026-8947
Debian:13thunderbird1:140.11.0esr-1~deb13u1DEBIAN-CVE-2026-8947
Debian:14thunderbird1:140.11.0esr-1DEBIAN-CVE-2026-8947
Rocky Linux:10firefox0:140.11.0-1.el10_2RLSA-2026:21380
Rocky Linux:8firefox0:140.11.0-1.el8_10RLSA-2026:21382
Rocky Linux:9firefox0:140.11.0-1.el9_8RLSA-2026:21378
Rocky Linux:10thunderbird0:140.11.0-1.el10_2RLSA-2026:22325
Rocky Linux:8thunderbird0:140.11.0-1.el8_10RLSA-2026:22643
Rocky Linux:9thunderbird0:140.11.0-1.el9_8RLSA-2026:21381
Ubuntu:22.04:LTSmozjs102no fix listedUBUNTU-CVE-2026-8947
Ubuntu:24.04:LTSmozjs102no fix listedUBUNTU-CVE-2026-8947
Ubuntu:24.04:LTSmozjs115no fix listedUBUNTU-CVE-2026-8947
Ubuntu:22.04:LTSmozjs78no fix listedUBUNTU-CVE-2026-8947
Ubuntu:22.04:LTSmozjs91no fix listedUBUNTU-CVE-2026-8947
Ubuntu:22.04:LTSthunderbirdno fix listedUBUNTU-CVE-2026-8947

Affected products (as reported)

VendorProductVersions
Mozilla Firefox see references
Mozilla Thunderbird see references

Weakness: CWE-416, CWE-825 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

References