CVE-2026-113868
MEDIUM
MEDIUM
Priority: 0.02
BB Relevance:
51/100
Published: 2026-10-20
Modified: 2026-10-22
First seen: 2026-10-29
Status: active
Attack Surface
Network
No Interaction
CVSS Vector Breakdown
AV:
Network
AC:
High
PR:
Low
UI:
None
S:
Unchanged
C:
None
I:
None
A:
High
Description
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.