CVE Catalog

CVE-2025-21994

HighCVSS 7.6
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.28%

20th percentile - higher than 20% of all known CVEs

Summary

In the SMB server (ksmbd) in the Linux kernel, incorrect validation of the num_aces field in smb_acl was found. The parse_dcal() function used a wrong condition that could allow allocating an array of size ULONG_MAX, leading to overflow.

Risk Assessment

Incorrect validation could allow a remote attacker to cause excessive memory allocation or buffer overflow, potentially leading to SMB server crash or arbitrary code execution.

Recommendation

Update the Linux kernel to a version containing the fix for CVE-2025-21994, which uses the size field from smb_acl for proper ACE count validation.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix incorrect validation for num_aces field of smb_acl parse_dcal() validate num_aces to allocate posix_ace_state_array. if (num_aces > ULONG_MAX / sizeof(struct smb_ace *)) It is an incorrect validation that we can create an array of size ULONG_MAX. smb_acl has ->size field to calculate actual number of aces in request buffer size. Use this to check invalid num_aces.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS