CVE-2026-58216

Samba: kpasswd service: kpasswd packet that contains malformed asn.1 might cause the server to access 6 bytes of unallocated memory leading server to crash

Description

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.

Scores

Weaknesses (CWE)

• CWE-125

European references

• ENISA EUVD · EUVD-2026-51177
• GCVE · GCVE-0-2026-58216

CERT-FR advisories

• CERTFR-2026-AVI-0939 — Multiples vulnérabilités dans Samba · cert.ssi.gouv.fr

Affected products

References

• https://access.redhat.com/security/cve/CVE-2026-58216
• https://bugzilla.redhat.com/show_bug.cgi?id=2502721
• https://bugzilla.samba.org/show_bug.cgi?id=16087
• https://www.samba.org/samba/security/CVE-2026-58216.html

Sources