CVE-2026-4371 — Out of bounds read in IMAP parsing
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…
Published: 2026-03-24 · CVSS: 7.4 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7