CVE-2026-58218

Samba: dns signing dos via tkey name cache exhaustion

Published Jul 30, 2026 CVSS 3.1 · 5.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

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

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

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Jul 30, 2026, 5:37 PM
Reserved
Jun 29, 2026, 6:13 PM
Status
Awaiting Analysis
Published
Jul 30, 2026, 2:17 PM
Modified
Jul 30, 2026, 7:18 PM
Severity
Moderate
Public date
Jul 28, 2026, 10:00 AM