An out-of-bounds read flaw was found in the way curl handled NTLMv2 type-2 headers. When connecting to a remote malicious server which uses NTLM authentication, the flaw could cause curl to crash.
libcurl versions from 7.36.0 to before 7.64.0 is vulnerable to a heap buffer out-of-bounds read.
The function handling incoming NTLM type-2 messages (`lib/vauth/ntlm.c:ntlm_decode_type2_target`) does not validate incoming data correctly and is subject to an integer overflow vulnerability.
Using that overflow, a malicious or broken NTLM server could trick libcurl to accept a bad length + offset combination that would lead to a buffer read out-of-bounds.
Bug introduced by:
Name: Daniel Stenberg (the Curl project)
Upstream: Wenxiang Qian (Tencent Blade Team)
Created curl tracking bugs for this issue:
Affects: fedora-all [bug 1672902]
Turn off NTLM authentication.
The versions of curl package shipped with Red Hat Enterprise Linux 5, 6, and 7 do not support NTLMv2 type-2 headers, hence they are not affected by this flaw.