CVE-2026-58218
Samba: dns signing dos via tkey name cache exhaustion
- Published
- Updated
- Reserved
- Assigned by
- redhat
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.
Timeline
ID reserved
By redhat
- 31 days later
· 31 days later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| redhatCNA (assigner) | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| NVDNVD · Awaiting Analysis | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
- EPSS (exploitation in 30 days)
- 0.78% · top 44% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Weakness
Affected products
Red Hat · Red Hat Enterprise Linux 10
All versions: unknown
Red Hat · Red Hat Enterprise Linux 6
All versions: unknown
Red Hat · Red Hat Enterprise Linux 6
All versions: unknown
Red Hat · Red Hat Enterprise Linux 7
All versions: unknown
Red Hat · Red Hat Enterprise Linux 8
All versions: unknown
Red Hat · Red Hat Enterprise Linux 9
All versions: unknown
Red Hat · Red Hat OpenShift Container Platform 4
All versions: unknown
References (4)
- https://access.redhat.com/security/cve/CVE-2026-58218 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2502728 (opens in a new tab)issue-trackingx_refsource_REDHAT
- https://bugzilla.samba.org/show_bug.cgi?id=16115 (opens in a new tab)
- https://www.samba.org/samba/security/CVE-2026-58218.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-58218)Record last updated .