Bug 2527116 (CVE-2026-84640)

Summary: CVE-2026-84640 thunderbird: One byte overflow read in mail parser
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: gotiwari, jhorak, mvyas, rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Thunderbird. A remote attacker could exploit this vulnerability by sending a maliciously constructed mail header. This could lead to a one-byte read past the end of a buffer, potentially resulting in information disclosure or other unpredictable behavior.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-01 21:43:38 UTC
A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155.

Comment 1 Jon Orris 2026-09-24 01:58:43 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:70642 https://access.redhat.com/errata/RHSA-2026:70642

Comment 2 Jon Orris 2026-09-24 01:58:45 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:70642 https://access.redhat.com/errata/RHSA-2026:70642

Comment 3 Jon Orris 2026-09-29 12:15:31 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:73130 https://access.redhat.com/errata/RHSA-2026:73130

Comment 4 Jon Orris 2026-09-30 14:19:31 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:73971 https://access.redhat.com/errata/RHSA-2026:73971