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No exploitation reportedFix available

CVE-2026-117887

Use-after-free in the DOM: Core & HTML component

No exploitation reported by the sources we read.

  • Published2026-10-27
  • WeaknessCWE-416

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

Use-after-free in the DOM: Core & HTML 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

Vendor advisories

  • CVE-2026-117887 Red Hat Product Security23 known affected

    firefox: thunderbird: Use-after-free in the DOM: Core & HTML component

    firefox as a component of Red Hat Enterprise Linux 10 · firefox.src as a component of Red Hat Enterprise Linux 10 · rhel10/firefox-flatpak as a component of Red Hat Enterprise Linux 10 · +20 more

Full record on NVD

Fix

  1. Workaround from the vendor Red Hat Product Security CVE-2026-117887 · 23 products--- CME Mitigation Guidance (2026-11-02) --- Disclaimer: The following mitigation solutions are provided as a courtesy, pending the application of an official patch. This content was generated utilizing AI tools in conjunction with data from https://cmetaxonomy.org. Customers are advised to indepen…
  2. No fix available, says the vendor Red Hat Product Security CVE-2026-117887 · 17 productsAffected
  3. No fix planned, says the vendor Red Hat Product Security CVE-2026-117887 · 6 productsOut of support scope

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:H
Published
2026-10-27
Last Modified
2026-11-04
NVD status
Deferred
GitHub Advisory
GHSA-9p2v-8p5p-q7hg

Frequently asked questions

What is CVE-2026-117887?

Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.

Is CVE-2026-117887 actively exploited?

Active exploitation of CVE-2026-117887 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-2026-117887?

CVE-2026-117887 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

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