Description
A flaw was found in Samba's internal DNS server where unauthenticated TKEY registration requests were added to the TKEY name cache before being rejected. A remote, unauthenticated attacker can exploit this behavior by sending a large number of TKEY requests with arbitrary names, exhausting the cache and evicting legitimate TKEY entries. This can prevent legitimate TSIG authentication for signed DNS queries, resulting in a denial of service.
Published: 2026-07-30
Score: 5.3 Medium
EPSS: 1.1% Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Debian DSA Debian DSA DSA-6401-1 samba security update
Ubuntu USN Ubuntu USN USN-8621-1 Samba vulnerabilities
History

Fri, 31 Jul 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Thu, 30 Jul 2026 20:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat openshift Container Platform
Samba
Samba samba
Vendors & Products Redhat openshift Container Platform
Samba
Samba samba

Thu, 30 Jul 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 30 Jul 2026 14:15:00 +0000

Type Values Removed Values Added
Description A flaw was found in Samba's internal DNS server where unauthenticated TKEY registration requests were added to the TKEY name cache before being rejected. A remote, unauthenticated attacker can exploit this behavior by sending a large number of TKEY requests with arbitrary names, exhausting the cache and evicting legitimate TKEY entries. This can prevent legitimate TSIG authentication for signed DNS queries, resulting in a denial of service.
Title Samba: dns signing dos via tkey name cache exhaustion
First Time appeared Redhat
Redhat enterprise Linux
Redhat openshift
Weaknesses CWE-410
CPEs cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat openshift
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}


Subscriptions

Redhat Enterprise Linux Openshift Openshift Container Platform
Samba Samba
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-07-30T17:37:18.466Z

Reserved: 2026-06-29T18:13:08.160Z

Link: CVE-2026-58218

cve-icon Vulnrichment

Updated: 2026-07-30T17:35:02.687Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-28T10:00:00Z

Links: CVE-2026-58218 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-02T05:30:06Z

Weaknesses