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No exploitation reportedFix available

CVE-2026-117912

Same-origin policy bypass in the CSS Parsing and Computation component

No exploitation reported by the sources we read.

  • Published2026-10-27
  • WeaknessCWE-346

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Same-origin policy bypass in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.

Timeline

dates in UTC
  1. 2026-10-2714:05CVE publishedCNA

Versions per branch

Products declared by the CNA2 products

As mozilla, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Mozilla Firefox

    Not affected ≥ 115.44, ≤ 115.* · ≥ 153.6, ≤ 153.* · ≥ 159

  • Mozilla Thunderbird

    Not affected ≥ 153.6, ≤ 153.* · ≥ 159

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-10-27

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • firefoxopenEuler:24.03-LTS-SP3all versions · fixed in 153.6.0-1.oe2403sp3
  • firefox-esropenSUSE:Tumbleweedall versions · fixed in 153.6.0-1.1and 1 other package
  • firefox-esrDebian:14all versions · no fixed version listedand 1 other package
  • firefox-esrDebian:13all versions · fixed in 153.6.0esr-1~deb13u1
  • firefox-esrDebian:12all versions · fixed in 153.6.0esr-1~deb12u2
  • MozillaFirefoxSUSE:Linux Enterprise Server LTSS Extended Security 12 SP5all versions · fixed in 153.6.0-118.19.2
  • MozillaFirefoxSUSE:Linux Enterprise Server 12 SP5-LTSSall versions · fixed in 153.6.0-118.19.2
  • mozjs102Ubuntu:24.04:LTSall versions · no fixed version listedand 1 other package

5 more package ranges on OSV.dev

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Published
2026-10-27
Last Modified
2026-11-04
NVD status
Deferred
GitHub Advisory
GHSA-wp78-8m8h-h6qj

Frequently asked questions

What is CVE-2026-117912?

Same-origin policy bypass in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.

Is CVE-2026-117912 actively exploited?

Active exploitation of CVE-2026-117912 has not been confirmed. Its EPSS score was 0.2% on 2026-11-04, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-117912?

CVE-2026-117912 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.

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