CVE-2023-25564Network attack vector

Memory corruption via uninitialized conversion length

Published Feb 14, 2023 · Updated Mar 10, 2025

Out-of-bounds write in GSS-NTLMSSP before 1.2.0 allows remote attackers to corrupt memory through a malformed NTLM UTF16 string. The ntlm_decode_u16l_str_hdr function uses an uninitialized outlen value to NUL-terminate the conversion buffer when iconv rejects malformed UTF16LE input. The flaw is reachable through gss_accept_sec_context in applications that accept attacker-controlled NTLM tokens, causing a crash or one-byte memory corruption.

CVSS severity6.5
Medium
EPSS probability1.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in GSS-NTLMSSP before 1.2.0 allows remote attackers to corrupt memory through a malformed NTLM UTF16 string. The ntlm_decode_u16l_str_hdr function uses an uninitialized outlen value to NUL-terminate the conversion buffer when iconv rejects malformed UTF16LE input. The flaw is reachable through gss_accept_sec_context in applications that accept attacker-controlled NTLM tokens, causing a crash or one-byte memory corruption.

The record

CVE
CVE-2023-25564
Published
Feb 14, 2023
Updated
Mar 10, 2025
Vendor
gssapi
Product
GSS-NTLMSSP
Classifications
CWE-787, T1210
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 14, 2023CVE publishedPublication date reported by the CVE source.
  2. Mar 10, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

gssapi · GSS-NTLMSSPversion=< 1.2.0

Published CVSS scores

8.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
6.5GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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