CVE-2026-74963

Firefox and Thunderbird suffer a same-origin policy bypass in their Networking: Cookies component, allowing cross-origin access to cookies. CVSS 5.4 (Medium). Fixed in Firefox 154, ESR 140.14, ESR 153.1, Thunderbird 154, 140.14, 153.1. No in-the-wild exploitation reported; user interaction requir...

CVE-2026-74976

CVE-2026-74976 is a JIT miscompilation in the JavaScript Engine: JIT component of Mozilla Firefox and Thunderbird. The vulnerability can lead to high confidentiality impact (information disclosure) with no integrity or availability impact, per the CVSS 3.1 score of 6.5 (MEDIUM) . Attack requires ...

CVE-2026-74936

A use-after-free in the JavaScript: WebAssembly component of Firefox/Thunderbird can lead to memory corruption and arbitrary code execution. CVSS 9.8 (network, no auth required). Fixed in Firefox 154, ESR 140.14, ESR 153.1, Thunderbird 154, 140.14, and 153.1; Debian and Slackware packages updated...

CVE-2026-74942

A privilege escalation flaw in Firefox's Remote Settings Client component allows a remote attacker to gain full system access with no authentication and low complexity. CVSS 8.8 (HIGH). CISA's SSVC rates technical impact as total but confirms no active exploitation. Fixed in Firefox 154, Firefox ...

CVE-2026-74973

CVE-2026-74973 is a race condition leading to use-after-free in the Graphics component of Mozilla Firefox and Thunderbird. The CVSS 3.1 score is 4.2 (Medium) , reflecting a network attack vector with high complexity, required user interaction, and low impact on confidentiality and integrity with ...

CVE-2026-74968

Firefox's WebRender component has a site isolation flaw allowing cross-site data access or tampering, rated CVSS 5.4 (Medium). Fixed in Firefox 154 and Firefox ESR 153.1. No in-the-wild exploitation reported. Users should update immediately. Mozilla advisories: mfsa2026-74, mfsa2026-77.

CVE-2026-74972

Information disclosure in Firefox/Thunderbird's DOM: Push Subscriptions component exposes sensitive data to malicious sites. CVSS 4.3 (MEDIUM), network-reachable with user interaction required. Fixed in Firefox 154, ESR 140.14/153.1, Thunderbird 154/140.14/153.1. No in-the-wild exploitation repor...

CVE-2026-74974

The vulnerability is a same-origin policy bypass in the Graphics: ImageLib component of Firefox and Thunderbird. Affected versions include Firefox ESR 140.13, ESR 153.0, and Thunderbird ESR 140.13, ESR 153.0. Remediation is to upgrade to Firefox ESR 140.14, ESR 153.1, Thunderbird 140.14, or Thund...

CVE-2026-74958

CVE-2026-74958 is an information disclosure vulnerability in the WebRTC component of Mozilla Firefox and Thunderbird. The CVSS 3.1 score is 7.5 (HIGH) , with a network attack vector requiring no privileges or user interaction, and a high impact on confidentiality. CISA SSVC assesses exploitation ...