What’s Vulnerable › Vulnerabilities

CVE-2026-98405: smb: client: fix missing iov bounds check in parse_posix_sids()

• Severity: high (CVSS 8.1 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: 2026-10-14 · updated 2026-10-24

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix missing iov bounds check in parse_posix_sids() In parse_posix_sids(), sidsbuf_end is calculated using the server-supplied out_len without being validated against the actual length of the received iov (iov_len). If a server provides an inflated out_len, sidsbuf_end will point past the end of the iov. This defeats the bounds guards in posix_info_sid_size(), allowing out-of-bounds reads into adjacent kernel memory. Fix this by rejecting responses where the calculated sidsbuf_end would exceed the received iov boundaries or cause pointer wraparound.

Affected products

• Linux kernel: from 6.6.32 before 6.6.158; 6.8 — fixed in 6.6.158, 7.3

How to fix

Upgrade to a fixed version: Linux kernel 6.6.158, 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/2f8ed71aaaba3bc8b19cd9930cc62e63e142b299
• https://git.kernel.org/stable/c/b09d092eb24ad0110f16a9b7c1ed5d2a0c1733dc
• https://git.kernel.org/stable/c/b862996e5105be1293da9cdc85da77b76021c3bd
• https://git.kernel.org/stable/c/d91b9a3b2b38e5ac1b51e9e5b23fe53ad7b49644
• https://git.kernel.org/stable/c/eac6917a42899aad0617bbf04798c5dd946a1fe5

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