Samba: vfs_worm does not block directory modification

Summary

A flaw was found in Samba’s vfs_worm module. The module is intended to provide write-once, read-many (WORM) protections by preventing modification of files after a configurable grace period. Due to insufficient validation during rename operations, an authenticated user with write access to a share could overwrite a protected file by renaming a newly created file over the existing WORM-protected file.

Timeline

1. May 27, 2026, 12:09 PM UTCCVE published
2. May 29, 2026, 3:35 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Oct 15, 2026, 4:58 PM UTCRecord last updated

Affected versions

• samba

  Version range not reported

• samba

  Version range not reported

• samba

  Version range not reported

• samba

  Version range not reported

• samba

  Version range not reported

• samba

  Version range not reported

• samba

  Version range not reported

• samba

  Version range not reported

• samba

  Version range not reported

• samba

  Version range not reported

• samba

  Version range not reported

• openshift/ose-rhel-coreos-8

  Version range not reported

• openshift/ose-rhel-coreos-9

  Version range not reported

• openshift/ose-rhel-coreos-9

  Version range not reported

• openshift/ose-rhel-coreos-9

  Version range not reported

• openshift/ose-rhel-coreos-9

  Version range not reported

• openshift/ose-rhel-coreos-9

  Version range not reported

• openshift/ose-rhel-coreos-9

  Version range not reported

• openshift/ose-rhel-coreos-9

  Version range not reported

• samba

  Version range not reported

• samba4

  Version range not reported

• samba

  Version range not reported

References 25