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PatchSiren cyber security CVE debrief

CVE-2026-6780 Mozilla CVE debrief

Mozilla Firefox and Thunderbird have addressed a denial-of-service vulnerability in the Audio/Video: Playback component. This issue was fixed in Firefox 150 and Thunderbird 150. Defenders should assess exposure, particularly for systems using these applications, and prioritize verification of affected versions and remediation. The vulnerability affects the Audio/Video: Playback component, potentially impacting service availability. Defenders should verify if Mozilla Firefox or Thunderbird is used in the environment and assess exposure. They should check if the version of Firefox is less than 150 or Thunderbird is less than 150. Updating Firefox to version 150 or later and Thunderb

Vendor
Mozilla
Product
Firefox
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-21
Original CVE updated
2026-10-26
Advisory published
2026-04-21
Advisory updated
2026-10-26

Who should care

Defenders responsible for systems using Mozilla Firefox or Thunderbird should assess exposure and prioritize verification of affected versions and remediation.

Why it matters

A denial-of-service vulnerability in the Audio/Video: Playback component of Mozilla Firefox and Thunderbird was addressed in Firefox 150 and Thunderbird 150. Defenders should assess exposure, particularly for systems using these applications, and prioritize verification of affected versions and remediation.

  • Defenders should verify if Mozilla Firefox or Thunderbird is used in the environment and assess exposure.
  • Defenders should check if the version of Firefox is less than 150 or Thunderbird is less than 150.
  • Defenders should update Firefox to version 150 or later and Thunderbird to version 150 or later.
  • Defenders should review vendor advisories for additional information.

Technical summary

A denial-of-service vulnerability exists in the Audio/Video: Playback component of Mozilla Firefox and Thunderbird. This issue was addressed in Firefox 150 and Thunderbird 150. The vulnerability could potentially impact service availability. Defenders should prioritize verification of affected versions and remediation, especially for systems using Mozilla Firefox and Thunderbird. The CVE record and NVD entry provide details on the denial-of-service vulnerability in Mozilla Firefox and Thunderbird. Vendor advisories are available for further information.

Defensive priority

Defenders should prioritize verification of affected versions and remediation, especially for systems using Mozilla Firefox and Thunderbird.

Recommended defensive actions

  • Verify if Mozilla Firefox or Thunderbird is used in the environment.
  • Check if the version of Firefox is less than 150 or Thunderbird is less than 150.
  • Update Firefox to version 150 or later and Thunderbird to version 150 or later.
  • Review vendor advisories for additional information.

Evidence notes

The CVE record and NVD entry provide details on the denial-of-service vulnerability in Mozilla Firefox and Thunderbird. Vendor advisories are available for further information.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-6780 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-6780

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-6780 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-6780

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.