CVE-2026-91926
Gss-ntlmssp: gss-ntlmssp: memory leak in ntlm_decode_target_info via duplicated av_pair entries in ntlm challenge
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
3.7
Gss-ntlmssp: gss-ntlmssp: memory leak in ntlm_decode_target_info via duplicated av_pair entries in ntlm challenge
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.
- Record
CVE-2026-91926- CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-401
- Updated
- 2026-11-06
EUVDEUVD-2026-78441
3.7
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.
- Record
EUVD-2026-78441- CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-06
GitHub AdvisoriesGHSA-x7fj-4fx4-9f96
3.7
A flaw was found in gss-ntlmssp. A memory leak occurs in the NTLM target-info parser when a...
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.
- Record
GHSA-x7fj-4fx4-9f96- CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-401
- Updated
- 2026-11-02
NVD
3.7
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.
- Record
CVE-2026-91926- CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-401
- Updated
- 2026-11-06
OSVDEBIAN-CVE-2026-91926
3.7
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.
- Record
DEBIAN-CVE-2026-91926- CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-07
OSVUBUNTU-CVE-2026-91926
3.7
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.
- Record
UBUNTU-CVE-2026-91926- CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
OSVAZL-107957 No score
CVE-2026-91926 affecting package gssntlmssp 1.3.1-1
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.
- Record
AZL-107957- Updated
- 2026-11-05
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
gssntlmsspAzure Linux:3 |
through 1.3.1-1 | None known |
gss-ntlmsspDebian:12 |
All versions, plus listed versions 1.2.0-11.3.1-1 |
None known |
gss-ntlmsspDebian:13 |
All versions, plus listed versions 1.2.0-11.3.1-1 |
None known |
gss-ntlmsspDebian:14 |
All versions, plus listed versions 1.2.0-11.3.1-1 |
None known |
gss-ntlmsspUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 0.6.0-10.7.0-3~ubuntu0.16.04.10.7.0-3~ubuntu0.16.04.1+esm1 |
None known |
gss-ntlmsspUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 0.7.0-30.7.0-40.7.0-4build10.7.0-4build30.7.0-4ubuntu0.18.04.1~esm1 |
None known |
gss-ntlmsspUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 0.7.0-4build30.7.0-4ubuntu0.20.04.1~esm1 |
None known |
gss-ntlmsspUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 0.7.0-4build30.7.0-4build40.7.0-4ubuntu0.22.04.1~esm1 |
None known |
gss-ntlmsspUbuntu:24.04:LTS |
All versions, plus listed versions 1.2.0-11.2.0-1build11.2.0-1build21.2.0-1build3 |
None known |
gss-ntlmsspUbuntu:26.10 |
All versions, plus listed versions 1.2.0-1build51.3.1-11.3.1-1build1 |
None known |
gss-ntlmsspUbuntu:26.04:LTS |
All versions, plus listed versions 1.2.0-1build41.2.0-1build5 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-91926 is a low vulnerability (CVSS 3.7) in Red Hat Enterprise Linux 8, published September 15, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.37%, the 31st percentile. No source names a fixed version.