CVE-2026-46155: smb/client: fix out-of-bounds read in smb2_compound_op()

Severity: critical (CVSS 9.1 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: 2026-05-28 · updated 2026-10-19
Weakness: CWE-125

Description

In the Linux kernel, the following vulnerability has been resolved: smb/client: fix out-of-bounds read in smb2_compound_op() If a server sends a truncated response but a large OutputBufferLength, and terminates the EA list early, check_wsl_eas() returns success without validating that the entire OutputBufferLength fits within iov_len. Then smb2_compound_op() does: memcpy(idata->wsl.eas, data[0], size[0]); Where size[0] is OutputBufferLength. If iov_len is smaller than size[0], memcpy can read beyond the end of the rsp_iov allocation and leak adjacent kernel heap memory.

Affected products

Linux kernel: from 6.6.32 before 6.6.140; from 6.9 before 6.12.88; from 6.13 before 6.18.30; from 6.19 before 7.0.7; 7.1-rc1, 7.1-rc2 — fixed in 6.12.88, 6.18.30, 6.6.140, 7.0.7

How to fix

Upgrade to a fixed version: Linux kernel 6.12.88, 6.18.30, 6.6.140, 7.0.7. Check the vendor advisory for mitigations.

References

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