CVE-2026-16405
Mozilla FirefoxVulnerabilityCVSS 7.5Patched
Information disclosure in the Networking: WebSockets component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.
No public exploitation has been reported so far. A fixed version is available (see the table below).
Recommended action: Update to the fixed version listed for your distribution using the native package manager.
Severity metrics
CVSS 3.1 : 7.5 HIGH
Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
Confidentiality impactHigh
Integrity impactNone
Availability impactNone
Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Affected & fixed versions by distribution
Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.
| Distribution | Package | Affected | Fixed version | Status |
|---|---|---|---|---|
| Debian:11 | firefox-esr | - | 140.13.0esr-1~deb11u1 | fixed |
| Debian:12 | firefox-esr | - | 140.13.0esr-1~deb12u1 | fixed |
| Debian:13 | firefox-esr | - | 140.13.0esr-1~deb13u1 | fixed |
| Debian:14 | firefox-esr | - | 140.13.0esr-1 | fixed |
| Debian:11 | thunderbird | - | - | affected (no fix yet) |
| Debian:12 | thunderbird | - | - | affected (no fix yet) |
| Debian:13 | thunderbird | - | - | affected (no fix yet) |
| Debian:14 | thunderbird | - | - | affected (no fix yet) |
| SUSE:Linux Enterprise Server 12 SP5-LTSS | MozillaFirefox | - | 140.13.0-112.324.2 | fixed |
| SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5 | MozillaFirefox | - | 140.13.0-112.324.2 | fixed |
| SUSE:Linux Enterprise Module for Desktop Applications 15 SP7 | MozillaFirefox | - | 140.13.0-150200.152.248.1 | fixed |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | MozillaFirefox | - | 140.13.0-150200.152.248.1 | fixed |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-LTSS | MozillaFirefox | - | 140.13.0-150200.152.248.1 | fixed |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | MozillaFirefox | - | 140.13.0-150200.152.248.1 | fixed |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS | MozillaFirefox | - | 140.13.0-150200.152.248.1 | fixed |
| SUSE:Linux Enterprise Server 15 SP4-LTSS | MozillaFirefox | - | 140.13.0-150200.152.248.1 | fixed |
| SUSE:Linux Enterprise Server 15 SP5-LTSS | MozillaFirefox | - | 140.13.0-150200.152.248.1 | fixed |
| SUSE:Linux Enterprise Server 15 SP6-LTSS | MozillaFirefox | - | 140.13.0-150200.152.248.1 | fixed |
| SUSE:Linux Enterprise Server for SAP Applications 15 SP4 | MozillaFirefox | - | 140.13.0-150200.152.248.1 | fixed |
| SUSE:Linux Enterprise Server for SAP Applications 15 SP5 | MozillaFirefox | - | 140.13.0-150200.152.248.1 | fixed |
| SUSE:Linux Enterprise Server for SAP Applications 15 SP6 | MozillaFirefox | - | 140.13.0-150200.152.248.1 | fixed |
| openSUSE:Tumbleweed | MozillaFirefox | - | 153.0-1.1 | fixed |
| openSUSE:Tumbleweed | MozillaThunderbird | - | 140.13.0-1.1 | fixed |
| openSUSE:Tumbleweed | firefox-esr | - | 140.13.0-1.1 | fixed |