VulnerabilityModified
CVE-2026-8948
Same-origin policy bypass in the DOM: Networking component.
CRITICAL 9.1EPSS 0.42%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.42%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
- CVSS 3.1
- 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 0.42% probability · 36th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-942, CWE-79
- Affected
- mozilla/firefox · mozilla/thunderbird
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2038803Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-46/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-50/Vendor Advisory
- https://access.redhat.com/security/cve/CVE-2026-8948
- https://bugzilla.redhat.com/show_bug.cgi?id=2479850
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-8948.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.