Medium severity5.4NVD Advisory· Published Aug 18, 2026· Updated Aug 19, 2026
CVE-2026-74963
CVE-2026-74963
Description
Same-origin policy bypass in the Networking: Cookies component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
20cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*+ 2 more
- cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*range: <154.0.0
- cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*range: <140.14.0
- (no CPE)range: up to 154
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*+ 2 more
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*range: <154.0
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*range: <140.14.0
- (no CPE)range: up to 154
- osv-coords14 versionspkg:apk/chainguard/firefoxpkg:apk/chainguard/firefox-docker-selenium-compatpkg:apk/wolfi/firefoxpkg:apk/wolfi/firefox-docker-selenium-compatpkg:rpm/almalinux/firefoxpkg:rpm/almalinux/firefox-x11pkg:rpm/almalinux/thunderbirdpkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Tumbleweedpkg:rpm/opensuse/MozillaThunderbird&distro=openSUSE%20Tumbleweedpkg:rpm/opensuse/firefox-esr&distro=openSUSE%20Tumbleweedpkg:rpm/opensuse/mozilla-nspr&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/mozilla-nss&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/rust-cbindgen&distro=openSUSE%20Leap%2016.0
< 154.0-r0+ 13 more
- (no CPE)range: < 154.0-r0
- (no CPE)range: < 154.0-r0
- (no CPE)range: < 154.0-r0
- (no CPE)range: < 154.0-r0
- (no CPE)range: < 140.14.0-1.el9_8.alma.1
- (no CPE)range: < 140.14.0-1.el9_8.alma.1
- (no CPE)range: < 140.14.0-1.el9_8.alma.1
- (no CPE)range: < 140.14.0-160000.1.1
- (no CPE)range: < 154.0-1.1
- (no CPE)range: < 140.14.0-1.1
- (no CPE)range: < 153.1.0-1.1
- (no CPE)range: < 4.39-160000.1.1
- (no CPE)range: < 3.125-160000.1.1
- (no CPE)range: < 0.29.4+git0-160000.1.1
Patches
Vulnerability mechanics
References
7- www.mozilla.org/security/advisories/mfsa2026-74/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-76/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-77/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-78/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-79/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2026-80/nvdVendor Advisory
- bugzilla.mozilla.org/show_bug.cginvdPermissions Required
News mentions
1- Mozilla Thunderbird: 25 Vulnerabilities Disclosed, Ranging from Critical to Medium SeverityVypr Intelligence · Aug 18, 2026