CVE-2023-5568Network attack vector

Authenticated KDC crash via freshness-token under-allocation

Published Oct 24, 2023 · Updated Sep 2, 2025

Heap overflow in Samba 4.19 before 4.19.2 allows remote authenticated users to crash the Heimdal KDC via a freshness token. The KDC allocates too little memory for the heim_octet_string that stores the supplied token, causing an out-of-bounds heap write. Exploitation requires valid network credentials and a Samba AD DC using the Heimdal KDC; Red Hat states that its RHEL and Fedora builds omit Heimdal.

CVSS severity5.9
Medium
EPSS probability1.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap overflow in Samba 4.19 before 4.19.2 allows remote authenticated users to crash the Heimdal KDC via a freshness token. The KDC allocates too little memory for the heim_octet_string that stores the supplied token, causing an out-of-bounds heap write. Exploitation requires valid network credentials and a Samba AD DC using the Heimdal KDC; Red Hat states that its RHEL and Fedora builds omit Heimdal.

The record

CVE
CVE-2023-5568
Published
Oct 24, 2023
Updated
Sep 2, 2025
Vendor
Red Hat
Product
Red Hat Gluster Storage
Classifications
CWE-122, CWE-787, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 2, 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?

Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Red Hat · Red Hat Gluster StorageAffected versions are unavailable in this record.

Published CVSS scores

5.9Red HatCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H
6.5NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CWE-787Out-of-bounds Write
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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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