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Review reviewHigh

CVE-2023-54250

Linux

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.

CVSS
8.2
EPSS
0.42%
34.5% percentile
CISA KEV
Not listed
Published
2025.12.30
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.42%
Technical severityCVSS 8.2

Vulnerability overview

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.

Affected product and versions

Product
Linux
Affected versions
>= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < 39f5b4b313b445c980a2a295bed28228c29228ed, >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < a2f6ded41bec1d3be643c80a5eb97f1680309001, >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < f02edb9debbd36f44efa7567031485892c7df60d, >= e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 < e7067a446264a7514fa1cfaa4052cdb6803bc6a2, >= 5.15
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
CWE
Not available