CVE-2026-8971 json
Same-origin policy bypass in the Networking: JAR component
published 2026-05-19 5 mo ago modified 2026-07-23 3 mo 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 151.0.0
- mozilla thunderbird 151.0.0
- 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
Vendor 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
- 5 mo ago
Exploit prediction
0.21% chance of exploitation in the next 30 days, higher than 10% of all scored CVEs (FIRST EPSS, 2026-11-08).
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 Vulns 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.