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CVE-2026-45186VulnerabilityPublished

Red Hat Security Advisory: firefox security, bug fix, and enhancement update

Affects Red Hat firefox security,Source GCVE Database

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Authoritative record:CVE-2026-45186· Low 2.9

Not known to be exploited · CVSS 2.9 Low : upgrade Red Hat libexpat to 2.8.1 when convenient.

Data as of 12 Nov 2026, 12:17 UTC

CVSS 3.1 base score
2.9Low
How severe the flaw is on the 0–10 CVSS scale.

Contested

Scorers differ by 2 or more points
CVSS scores by source
CNA (mitre)CVSS 3.12.9
ADP (redhat-SADP)CVSS 3.17.5
Patch
Available – fixed in 2.8.1
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 12 Nov 2026.

What to do

Upgrade libexpat and libexpat/libexpat to 2.8.1.

Affected software

ProductAffectedFixed in
libexpat projectlibexpatAffected
  • <2.8.1
Fixed in
  • 2.8.1
GitHublibexpat/libexpatpkg:github/libexpat/libexpatOther threatsAffected
  • <2.8.1
Fixed in
  • 2.8.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A security update for Mozilla Firefox and Thunderbird is available for Red Hat Enterprise Linux 8.4 Extended Life Cycle and related variants. Users should apply the update as provided by Red Hat to remediate these vulnerabilities. For detailed update instructions, refer to the Red Hat advisory at https://access.redhat.com/articles/11258. Since the update addresses all listed vulnerabilities, no additional mitigations are required beyond applying the official patch.

Description

This Red Hat Security Advisory addresses multiple security vulnerabilities in Mozilla Firefox and Thunderbird, including denial of service, mitigation bypasses, spoofing, privilege escalation, use-after-free, information disclosure, sandbox escapes, race conditions, integer overflows, and incorrect boundary conditions across various components such as XML, DOM, JavaScript engine, networking, graphics, and storage. The update is rated as important by Red Hat and provides fixes for these issues in Red Hat Enterprise Linux 8.4 variants. The advisory includes a comprehensive list of CVEs affecting Firefox and Thunderbird components, emphasizing the critical nature of these vulnerabilities.

References

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