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Vulnerabilities

Vulnerability · CVE-2026-8961

Spoofing issue in the Form Autofill component.

Published May 19, 2026 · catalog updated Jul 23, 2026 · Spoofing issue in the

Check if you run it

No confirmed exploitation is on record for CVE-2026-8961. EPSS is 0.35%. Act only if a listed version of Spoofing issue in the is installed.

Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.35%
Remediation
Advisory link
Affected products
cpe mozilla/firefox · cpe mozilla/thunderbird

Spoofing issue in the Form Autofill component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe mozilla/firefoxversion unspecified
  • cpe mozilla/thunderbirdversion unspecified

How to fix CVE-2026-8961

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-8961. EPSS is 0.35%. Act only if a listed version of Spoofing issue in the is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-290: Authentication Bypass by Spoofing. EPSS 0.35%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. May 19, 2026 · NIST NVD

    Detected

    Spoofing issue in the Form Autofill component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

  2. Jul 23, 2026 · NIST NVD

    Updated

    Spoofing issue in the Form Autofill component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Sources

  • CVE.orgVulnerability recordCVE-2026-8961

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-8961

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2026-8961

    Spoofing issue in the Form Autofill component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.