CVE-2026-56968Public exploitNetwork attack vector

Heap disclosure via short NTLM challenge

Published Jun 23, 2026 · Updated Jun 23, 2026

Memory disclosure in GNU SASL before 2.2.4 allows remote attackers controlling an NTLM server to read client heap data. _gsasl_ntlm_client_step accepts a short Type-2 challenge, copies it into a malloc-allocated fixed-size structure, and passes the uninitialized tail to libntlm. The leak requires an NTLM client connection to an attacker-controlled server, which receives the uninitialized bytes in the client's response.

CVSS severity3.7
Low
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory disclosure in GNU SASL before 2.2.4 allows remote attackers controlling an NTLM server to read client heap data. _gsasl_ntlm_client_step accepts a short Type-2 challenge, copies it into a malloc-allocated fixed-size structure, and passes the uninitialized tail to libntlm. The leak requires an NTLM client connection to an attacker-controlled server, which receives the uninitialized bytes in the client's response.

The record

CVE
CVE-2026-56968
Published
Jun 23, 2026
Updated
Jun 23, 2026
Vendor
The GnuPG Project
Product
GNU SASL
Classifications
CWE-839, CWE-908
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 23, 2026Record 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=0 <2.2.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The GnuPG Project · GNU SASLversion=0 <2.2.4

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
3.7MITRECVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-839Numeric Range Comparison Without Minimum Check
CWE-908Use of Uninitialized Resource

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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