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BoardVulnerabilities › CVE-2026-74990
9.8Critical CVE-2026-74990 Mozilla

Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153.

Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunder

What happened

Internally found bugs present in Thunderbird ESR 140.13, Thunderbird ESR 153.0 and Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

Does it affect you

Not enough information

No products recorded, so this cannot be matched against anything.

What to do

  • Follow the vendor advisory for the fixed release and any interim mitigation.
    mozilla.org
  • Follow the vendor advisory for the fixed release and any interim mitigation.
    mozilla.org
  • Follow the vendor advisory for the fixed release and any interim mitigation.
    mozilla.org
  • Follow the vendor advisory for the fixed release and any interim mitigation.
    mozilla.org

Vendor's affected list

firefox
Everything below 115.39.0

Sources

A verdict here is derived from what you told us and what the vendor published. It is not an assessment of your environment. Why we never say you are safe.