Bug 2426238 (CVE-2023-54250)

Summary: CVE-2023-54250 kernel: ksmbd: avoid out of bounds access in decode_preauth_ctxt()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2025-12-30 13:18:36 UTC 
In the Linux kernel, the following vulnerability has been resolved:

ksmbd: avoid out of bounds access in decode_preauth_ctxt()

Confirm that the accessed pneg_ctxt->HashAlgorithms address sits within
the SMB request boundary; deassemble_neg_contexts() only checks that the
eight byte smb2_neg_context header + (client controlled) DataLength are
within the packet boundary, which is insufficient.

Checking for sizeof(struct smb2_preauth_neg_context) is overkill given
that the type currently assumes SMB311_SALT_SIZE bytes of trailing Salt.
Comment 1 Alexander B 2025-12-30 23:03:31 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025123054-CVE-2023-54250-96bc@gregkh/T