CVE-2026-58218

MEDIUM

5.3

CVSS v3

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.

CWE-410

How to fix

Remediation Available

sambaDebian

Fixed in:2:4.22.10+dfsg-0+deb13u2CVE-2026-58218

Fixed in:2:4.24.5+dfsg-1CVE-2026-58218

sambaUbuntu

Fixed in:2:4.15.13+dfsg-0ubuntu1.13USN-8621-1

Fixed in:2:4.19.5+dfsg-4ubuntu9.7USN-8621-1

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

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

Exploit Intelligence

1.10%probability of exploitation in 30 days

63rdpercentile

Moderate risk: more likely to be exploited than 63% of all known CVEs.

References

Other references4

Related Vulnerabilities

Other CWE-410 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2022-40224	High	7.5	65%	-	-
CVE-2025-0453	High	7.5	10%	-	-
CVE-2022-2048	High	7.5	2.3%	-	Fix
CVE-2025-27479	High	7.5	2.0%	-	Fix
CVE-2018-13815	High	7.5	1.8%	-	Fix
CVE-2019-13921	High	7.5	1.4%	-	-

Common questions

How do I fix CVE-2026-58218?

Published advisories record a fix for 2 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2026-58218 being actively exploited?

Not that we know of. CVE-2026-58218 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.1% is the estimated probability that it will be exploited in the next 30 days. That is higher than 63% of all scored CVEs.

How severe is CVE-2026-58218?

CVE-2026-58218 has a CVSS v3 base score of 5.3, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-58218 affect?

Published advisories record a fix for samba (Debian), samba (Ubuntu). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-30.