CVE-2026-8971 json
Same-origin policy bypass in the Networking: JAR component
published 5mo ago modified 3mo ago also EUVD-2026-30919
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 10%
- public exploits
- 0
- none known
Summary
Same-origin policy bypass in the Networking: JAR component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
Patch / fix
- mozilla firefox 151
- mozilla firefox_esr 151
- mozilla thunderbird 151
- mozilla thunderbird_esr 151
- firefox-esr openSUSE Tumbleweed 153.0-1.1
- MozillaFirefox openSUSE Tumbleweed 151.0.1-1.1
opensuse advisories openSUSE-SU-2026:11373-1openSUSE-SU-2026:10863-1
Is CVE-2026-8971 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerVendor advisories
What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
red hat product security vex CVE-2026-8971 updated cvss 3.4
firefox: thunderbird: Same-origin policy bypass in the Networking: JAR component
-
Red Hat Enterprise Linux 6 firefox, thunderbird Red Hat Enterprise Linux 7 firefox, thunderbird Red Hat Enterprise Linux 8 firefox, thunderbird Red Hat Enterprise Linux 9 firefox, firefox-x11, thunderbird Red Hat Enterprise Linux 10 firefox, thunderbird, rhel10/firefox-flatpak, rhel10/thunderbird-flatpaknot affected: vulnerable code not present
Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 5mo ago
Exploit prediction
0.21% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
Affected products
- Mozilla Firefox
- Mozilla Thunderbird
Classification
- Weakness
-
- CWE-346 Origin Validation Error
References
-
mozilla.org
/security/advisories/mfsa2026-46/
vendor-advisory
-
mozilla.org
/security/advisories/mfsa2026-50/
vendor-advisory
-
bugzilla.mozilla.org
/show_bug.cgi?id=2032604
permissions-required
Sources
- CVE List CVE-2026-8971
- NVD CVE-2026-8971
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.