CVE-2026-91926 PUBLISHED

Gss-ntlmssp: gss-ntlmssp: memory leak in ntlm_decode_target_info via duplicated av_pair entries in ntlm challenge

Assigner: redhat
Reserved: 15.09.2026 Published: 15.09.2026 Updated: 15.09.2026

A flaw was found in gss-ntlmssp. A memory leak occurs in the NTLM target-info parser when a crafted NTLM CHALLENGE message contains duplicated string-valued AV_PAIR entries. The parser allocates memory for each string value but does not free the previous allocation when the same AV_PAIR type appears more than once, leaking the earlier allocation. A malicious or man-in-the-middle server can exploit this to cause gradual memory exhaustion on the client during NTLM authentication, leading to a denial of service.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS Score: 3.7

Product Status

Vendor Red Hat
Product Red Hat Enterprise Linux 8
Versions Default: affected

Workarounds

No mitigation is currently available that meets Red Hat Product Security's standards for usability, deployment, applicability, or stability.

Credits

  • Red Hat would like to thank Chase Bevan-Thomas (cbev0x) (Independent security researcher) for reporting this issue.

References

Problem Types

  • Missing Release of Memory after Effective Lifetime CWE