fs/smb/client: fix out-of-bounds read in cifs_sanitize_prepath_CVE-2026-43112

8.8 / 10

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Description

In the Linux kernel, the following vulnerability has been resolved:

fs/smb/client: fix out-of-bounds read in cifs_sanitize_prepath

When cifs_sanitize_prepath is called with an empty string or a string
containing only delimiters (e.g., "/"), the current logic attempts to
check *(cursor2 - 1) before cursor2 has advanced. This results in an
out-of-bounds read.

This patch adds an early exit check after stripping prepended
delimiters. If no path content remains, the function returns NULL.

The bug was identified via manual audit and verified using a
standalone test case compiled with AddressSanitizer, which
triggered a SEGV on affected inputs.

AI Analysis

Out-of-bounds read in cifs_sanitize_prepath function

Basic Information

ID CVE-2026-43112

Source Linux

Published May 6, 2026 at 07:40

Modified May 8, 2026 at 12:40

Affected Product

Vendor Linux

Product Linux

Version a31080899d5fdafcccf7f39dd214a814a2c82626

Affected Versions Linux Linux a31080899d5fdafcccf7f39dd214a814a2c82626
Linux Linux a31080899d5fdafcccf7f39dd214a814a2c82626
Linux Linux a31080899d5fdafcccf7f39dd214a814a2c82626
Linux Linux a31080899d5fdafcccf7f39dd214a814a2c82626
Linux Linux a31080899d5fdafcccf7f39dd214a814a2c82626
Linux Linux c63433a09d6ae4c226fcbc66da4c58fc189fd746
Linux Linux 5.16

AI Assessment

AI Score 8.8 / 10

AI Severity High

Vendor Linux

Product Linux Kernel

Version a31080899d5fdafcccf7f39dd214a814a2c82626, 5.16

References

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    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/smb/client: fix out-of-bounds read in cifs_sanitize_prepath\n\nWhen cifs_sanitize_prepath is called with an empty string or a string\ncontaining only delimiters (e.g., \"/\"), the current logic attempts to\ncheck *(cursor2 - 1) before cursor2 has advanced. This results in an\nout-of-bounds read.\n\nThis patch adds an early exit check after stripping prepended\ndelimiters. If no path content remains, the function returns NULL.\n\nThe bug was identified via manual audit and verified using a\nstandalone test case compiled with AddressSanitizer, which\ntriggered a SEGV on affected inputs.",
    "published": "2026-05-06T07:40:38.563Z",
    "modified": "2026-05-08T12:40:37.265Z",
    "type": "cve",
    "title": "fs/smb/client: fix out-of-bounds read in cifs_sanitize_prepath",
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    "references": "https://git.kernel.org/stable/c/5d4fe469fe7dbff7d874c196bb680a82f2625d95\nhttps://git.kernel.org/stable/c/2d29214448ec0f4e7e18bb1c14dd4a6c07f1c439\nhttps://git.kernel.org/stable/c/86f9c23e0814cfdffda9eedf0c591c51ba209010\nhttps://git.kernel.org/stable/c/49b1ce6d7cfb6c5a49f68bf5ccfcfb6ba14e63c3\nhttps://git.kernel.org/stable/c/78ec5bf2f589ec7fd8f169394bfeca541b077317",
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