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CVE-2026-58216 Red Hat CVE debrief

An out-of-bounds read flaw was found in Samba's Kerberos Key Distribution Center's (KDC) password change (kpasswd) service. When processing malformed ASN.1-encoded Kerberos password change request, Samba server miscalculates the structure size and attempts to read up to six bytes beyond the end of the allocated buffer. While this out-of-bounds read typically results in a harmless decryption failure, if the read hits unmapped memory, it causes the KDC process to crash. An authenticated attacker can send a specially crafted kpasswd request containing malformed ASN.1 data to trigger the out-of-bounds read, which may cause the KDC process to terminate, resulting in a denial of service.

Vendor
Red Hat
Product
Red Hat Enterprise Linux 10
CVSS
MEDIUM 5.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-30
Original CVE updated
2026-07-31
Advisory published
2026-07-30
Advisory updated
2026-07-31

Who should care

System administrators and security teams responsible for Samba installations, particularly those with exposed KDC services, should be aware of this vulnerability. They should review their current Samba configurations, verify potential exposure, and plan for remediation or mitigation strategies. Additionally, security teams should monitor for unusual KDC process termination and implement compensating controls to limit KDC service access if necessary.

Technical summary

The vulnerability is an out-of-bounds read flaw in Samba's Kerberos Key Distribution Center's (KDC) password change (kpasswd) service. An authenticated attacker can send a specially crafted kpasswd request containing malformed ASN.1 data to trigger the out-of-bounds read, which may cause the KDC process to terminate, resulting in a denial of service. This issue affects Samba installations with exposed KDC services, particularly those with weak access controls or exposed to untrusted networks.

Defensive priority

Medium priority due to authenticated attack vector and potential for denial of service

Recommended defensive actions

  • Inventory Samba installations and verify KDC service exposure
  • Implement compensating controls to limit KDC service access
  • Monitor for unusual KDC process termination
  • Apply vendor remediation when available
  • Review official advisories for remediation guidance
  • Track remediation exceptions and verify fixes
  • Conduct regular security audits to identify potential exposures

Evidence notes

Evidence from official sources indicates an out-of-bounds read flaw in Samba's KDC password change service. Limited information available on exploitability and affected systems. Further verification is needed to determine the scope of affected systems and potential impact. Defenders should review official advisories and monitor for unusual KDC process termination.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-58216 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-58216

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-58216 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-58216

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.