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Review reviewHigh

CVE-2026-31709

Linux Linux, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support

In the Linux kernel, the following vulnerability has been resolved: smb: client: validate the whole DACL before rewriting it in cifsacl build_sec_desc() and id_mode_to_cifs_acl() derive a DACL pointer from a server-supplied dacloffset and then use the incoming ACL to rebuild the chmod/chown security descriptor. The original fix only checked that the struct smb_acl header fits before reading dacl_ptr->size or dacl_ptr->num_aces. That avoids the immediate header-field OOB read, but the rewrite helpers still walk ACEs based on pdacl->num_aces with no structural validation of the incoming DACL...

CVSS
8.8
EPSS
0.26%
17.5% percentile
CISA KEV
Not listed
Published
2026.05.01
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.26%
Technical severityCVSS 8.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: smb: client: validate the whole DACL before rewriting it in cifsacl build_sec_desc() and id_mode_to_cifs_acl() derive a DACL pointer from a server-supplied dacloffset and then use the incoming ACL to rebuild the chmod/chown security descriptor. The original fix only checked that the struct smb_acl header fits before reading dacl_ptr->size or dacl_ptr->num_aces. That avoids the immediate header-field OOB read, but the rewrite helpers still walk ACEs based on pdacl->num_aces with no structural validation of the incoming DACL...

Affected product and versions

Product
Linux Linux, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support
Affected versions
>= bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 < b8603d9ae6c9087662b098619996bc4a8064319d, >= bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 < c2abdebf72000a64603ced84d36ccbd164f11391, >= bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 < 8e47d297e7cf9a6029a0d38e7b22faba7d7aaf12, >= bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 < d92f3f0b22414e7515696a02224d0af55e3004a3, >= bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 < ff0ca46b13b9ef6edbcd238a3b6caacfef8ba0e5, >= bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 < b78db9bddc84136f6a0bb49e8883cf200dfb87a8, >= bc3e9dd9d104ca1b75644eab87b38ce8a924aef4 < 0a8cf165566ba55a39fd0f4de172119dd646d39a, >= 5.12, >= 5.12 < 7.0.2
Fixed versions
7.0.2

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE
CWE-1288
CVE-2026-31709 — Linux Linux, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support | SECUFOCUS NOW