CVE-2023-4091

Summary

CVE-2023-4091 is a vulnerability affecting Samba, a common file-sharing software. The flaw enables SMB clients to truncate files, despite having read-only permissions, when the "acl_xattr" module is configured with "acl_xattr:ignore system acls = yes". The SMB protocol permits opening files with read-only access, but inadvertently sets the file size to zero when the client issues an OVERWRITE request. This vulnerability poses a risk because it bypasses kernel file system permissions checks, relying solely on Samba's permissions.

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