Vulnerability-Lookup

GHSA-QCXX-8H4X-9V7W

Vulnerability from github – Published: 2026-07-30 15:31 – Updated: 2026-07-30 15:31

Details

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.

Severity

5.3 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-58218"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-410"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-30T14:17:00Z",
    "severity": "MODERATE"
  },
  "details": "A flaw was found in Samba\u0027s 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.",
  "id": "GHSA-qcxx-8h4x-9v7w",
  "modified": "2026-07-30T15:31:51Z",
  "published": "2026-07-30T15:31:51Z",
  "references": [
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      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-58218"
    },
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      "type": "WEB",
      "url": "https://access.redhat.com/security/cve/CVE-2026-58218"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2502728"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.samba.org/show_bug.cgi?id=16115"
    },
    {
      "type": "WEB",
      "url": "https://www.samba.org/samba/security/CVE-2026-58218.html"
    }
  ],
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  "severity": [
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      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-58218 (GCVE-0-2026-58218)

Vulnerability from cvelistv5 – Published: 2026-07-30 14:01 – Updated: 2026-07-30 17:37

Title

Samba: dns signing dos via tkey name cache exhaustion

Summary

Severity

5.3 (Medium)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-30 17:34 UTC

CWE

CWE-410 - Insufficient Resource Pool

Assigner

redhat redhat root

References

4 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-58218	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2502728	issue-trackingx_refsource_REDHAT
https://bugzilla.samba.org/show_bug.cgi?id=16115
https://www.samba.org/samba/security/CVE-2026-582…

Impacted products

6 products

Vendor	Product	Version
Red Hat	Red Hat Enterprise Linux 10	cpe:/o:redhat:enterprise_linux:10
Red Hat	Red Hat Enterprise Linux 6	cpe:/o:redhat:enterprise_linux:6
Red Hat	Red Hat Enterprise Linux 7	cpe:/o:redhat:enterprise_linux:7
Red Hat	Red Hat Enterprise Linux 8	cpe:/o:redhat:enterprise_linux:8
Red Hat	Red Hat Enterprise Linux 9	cpe:/o:redhat:enterprise_linux:9
Red Hat	Red Hat OpenShift Container Platform 4	cpe:/a:redhat:openshift:4

Date Public

2026-07-28 10:00

Credits

Red Hat would like to thank Andrew Tridgell (Samba Team) and Tristan Madani (Talence Security) for reporting this issue.

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-QCXX-8H4X-9V7W

CVE-2026-58218 (GCVE-0-2026-58218)

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