access.redhat.comvdb entry
https://access.redhat.com/security/cve/CVE-2026-58218 CVE-2026-58218
MEDIUM
Samba: dns signing dos via tkey name cache exhaustion
Record summary
CVE-2026-58218 has a selected CVSS score of 5.3 (medium).
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.
Description source: CVE List
Exploitation context
CISA SSVC decision
ExploitationNone
AutomatableYes
Technical impactPartial
CISA Coordinator · SSVC 2.0.3 · Evaluated Jul 30, 2026 · Source: CVE List
Affected products and versions
7| Product | Source | Version range | Status |
|---|---|---|---|
Default status: unknown | CVE List | Version data not supplied | |
Default status: unknown | CVE List | Version data not supplied | |
Default status: unknown | CVE List | Version data not supplied | |
Default status: unknown | CVE List | Version data not supplied | |
Default status: unknown | CVE List | Version data not supplied | |
Default status: unknown | CVE List | Version data not supplied | |
Default status: unknown | CVE List | Version data not supplied | |
References
5RHBZ#2502728issue tracking
https://bugzilla.redhat.com/show_bug.cgi?id=2502728 bugzilla.samba.org
https://bugzilla.samba.org/show_bug.cgi?id=16115 nvd.nist.gov
https://nvd.nist.gov/vuln/detail/CVE-2026-58218 samba.org
https://www.samba.org/samba/security/CVE-2026-58218.html