CVE-2026-58218
Publication date 28 July 2026
Last updated 7 August 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| samba | 26.04 LTS resolute |
Fixed 2:4.23.6+dfsg-1ubuntu2.2
|
| 24.04 LTS noble |
Fixed 2:4.19.5+dfsg-4ubuntu9.7
|
|
| 22.04 LTS jammy |
Fixed 2:4.15.13+dfsg-0ubuntu1.13
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 16.04 LTS xenial |
Needs evaluation
|
|
| 14.04 LTS trusty |
Needs evaluation
|
Severity score breakdown
CVSS version: CVSS v3.0
Base score
5.3 · Medium
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References
Related Ubuntu Security Notices (USN)
- USN-8621-1
- Samba vulnerabilities
- 28 July 2026