CVE-2026-113868 — Uninitialized memory disclosure and out-of-bounds read in POP3 and SMTP NTLM authentication
When authenticating to a POP3 or SMTP server using NTLM, Thunderbird did not check whether the server's challenge was valid base64. A malicious server could send a challenge tha…
Published: 2026-10-20 · CVSS: 5.3 · CVSS 3.1
When authenticating to a POP3 or SMTP server using NTLM, Thunderbird did not check whether the server's challenge was valid base64. A malicious server could send a challenge that caused Thunderbird to include uninitialized heap memory in its NTLM response, disclosing that memory to the server. A challenge consisting only of base64 padding also caused an out-of-bounds read, crashing Thunderbird. This affected accounts configured to use NTLM or GSSAPI authentication. The uninitialized memory disclosure only affected NTLM. This vulnerability was fixed in Thunderbird 158.0.1 and Thunderbird 153.5.1.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7