5.3

CVE-2026-58218: Samba: dns signing dos via tkey name cache exhaustion

Awaiting analysis
AliasesUBUNTU-CVE-2026-58218DEBIAN-CVE-2026-58218
Published 30-07-2026Last modified 30-07-2026

Vulnerability summary

CVE-2026-58218 is a medium (CVSS 5.3) Insufficient Resource Pool vulnerability in samba. EPSS estimates a 0.78% chance of exploitation in the next 30 days, higher than 56% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.3, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.78%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 13 · Related 14
OPENSUSE-SU-2026:11431-1OPENSUSE-SU-2026:21475-1OPENSUSE-SU-2026:21540-1SUSE-SU-2026:22977-1SUSE-SU-2026:23003-1SUSE-SU-2026:23129-1

Timeline

  1. 30-07-2026
    PublishedVulnerability first disclosed.
  2. 30-07-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.78%

Chance of exploitation in the next 30 days

Percentile

56%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.78% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Debian1 product
  • sambaAll versions (No fix recorded) | < 2:4.22.10+dfsg-0+deb13u2 | < 2:4.24.5+dfsg-1
Ubuntu1 product
  • sambaAll versions (No fix recorded) | < 2:4.15.13+dfsg-0ubuntu1.13 | < 2:4.19.5+dfsg-4ubuntu9.7 | < 2:4.23.6+dfsg-1ubuntu2.2

2 vendors · 2 products

References

8 links