What’s Vulnerable › Vulnerabilities

CVE-2025-40099: cifs: parse_dfs_referrals: prevent oob on malformed input

• Severity: critical (CVSS 9.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-10-30 · updated 2026-10-19

Description

In the Linux kernel, the following vulnerability has been resolved: cifs: parse_dfs_referrals: prevent oob on malformed input Malicious SMB server can send invalid reply to FSCTL_DFS_GET_REFERRALS - reply smaller than sizeof(struct get_dfs_referral_rsp) - reply with number of referrals smaller than NumberOfReferrals in the header Processing of such replies will cause oob. Return -EINVAL error on such replies to prevent oob-s.

Affected products

• Linux kernel: 4.11 — fixed in 6.18

How to fix

Upgrade to a fixed version: Linux kernel 6.18. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/15c73964da9df994302f579ed14ee5fdbce7a332
• https://git.kernel.org/stable/c/6447b0e355562a1ff748c4a2ffb89aae7e84d2c9
• https://git.kernel.org/stable/c/8bc4a8d39bac23d8b044fd3e2dbfd965f1d9b058
• https://git.kernel.org/stable/c/bb0f2e66e1ac043a5b238f5bcab4f26f3c317039
• https://git.kernel.org/stable/c/cfacc7441f760e4a73cc71b6ff1635261d534657

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