What’s Vulnerable › Vulnerabilities

CVE-2023-54250: ksmbd: avoid out of bounds access in decode_preauth_ctxt()

• Severity: high (CVSS 8.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-30 · updated 2026-08-04

Description

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 products

• Linux kernel: 5.15 — fixed in 6.3

How to fix

Upgrade to a fixed version: Linux kernel 6.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/39f5b4b313b445c980a2a295bed28228c29228ed
• https://git.kernel.org/stable/c/a2f6ded41bec1d3be643c80a5eb97f1680309001
• https://git.kernel.org/stable/c/e7067a446264a7514fa1cfaa4052cdb6803bc6a2
• https://git.kernel.org/stable/c/f02edb9debbd36f44efa7567031485892c7df60d

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