CVE-2023-25564
gssntlmssp: memory corruption when decoding UTF16 strings
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · February 14, 2023
Updated · November 22, 2025
Description
A flaw was found in GSS-NTLMSSP, a mechglue plugin for the GSSAPI library that implements NTLM authentication. Memory corruption can be triggered when decoding UTF16 strings. The variable outlen was not initialized and could cause writing a zero to an arbitrary place in memory if the ntlm_str_convert() fails, which would leave outlen uninitialized. This issue can lead to a denial of service if the write hits unmapped memory or randomly corrupts a byte in the application memory space. This vulnerability can trigger an out-of-bounds write, leading to memory corruption, and can be triggered via the main gss_accept_sec_context entry point.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-787 · Out-of-bounds Write