PatchSiren cyber security CVE debrief
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.
Official resources
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-30T16:17:14.767Z and has not been modified since then.