libsoup: heap-based over-read in soup_ntlm_parse_challenge() in soup-auth-ntlm.c (CVE-2019-17266)

libsoup from versions 2.65.1 until 2.68.1 have a heap-based buffer over-read because soup_ntlm_parse_challenge() in soup-auth-ntlm.c does not properly check an NTLM message's length before proceeding with a memcpy.

References:

• https://nvd.nist.gov/vuln/detail/CVE-2019-17266
• https://security-tracker.debian.org/tracker/CVE-2019-17266

Affected branches:

• master (49536abf)
• 3.10-stable (8e6d8b01)