Riskcovery

CVE-2026-4371

Out of bounds read in IMAP parsing

State
Published
Severity
7.4 High
Published
Mar 24, 2026
Updated
Jul 15, 2026
Reserved
Mar 18, 2026

Read the record on cve.org

Description

A malicious mail server could send malformed strings with negative lengths, causing the parser to read memory outside the buffer. If a mail server or connection to a mail server were compromised, an attacker could cause the parser to malfunction, potentially crashing Thunderbird or leaking sensitive data. This vulnerability was fixed in Thunderbird 149 and Thunderbird 140.9.

Scores

CVSSScoreVectorSource
3.17.4 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:HCISA-ADP
3.18.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:Hredhat-SADP

Weaknesses

  • CWE-126 Buffer Over-read
  • CWE-130 Improper Handling of Length Parameter Inconsistency

Affected Products

ProductVersions
ThunderbirdMozilla
  • 140.9 through 140.*Not affected
  • 149 and laterNot affected

References

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