CVE-2026-58218

MEDIUMCVSS 5.3/10

Last modified

CVE-2026-58218 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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.

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.

Metrics

CVSS 3.1
5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
Red HatRed Hat Enterprise Linux 10All versions
Red HatRed Hat Enterprise Linux 6All versions
Red HatRed Hat Enterprise Linux 7All versions
Red HatRed Hat Enterprise Linux 8All versions
Red HatRed Hat Enterprise Linux 9All versions
Red HatRed Hat OpenShift Container Platform 4All versions

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-58218?
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.
How severe is CVE-2026-58218?
CVE-2026-58218 has a CVSS score of 5.3/10 (MEDIUM severity).
How do I fix CVE-2026-58218?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST