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Review reviewHigh

CVE-2026-53390

Linux Linux, linux kernel

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix out-of-bounds read in smb_check_perm_dacl() The permission-check ACE walk in smb_check_perm_dacl() validates the ACE header size and caps sid.num_subauth at SID_MAX_SUB_AUTHORITIES, but it never checks that ace->size is actually large enough to contain num_subauth sub-authorities before compare_sids() dereferences them. CIFS_SID_BASE_SIZE covers the SID header up to but excluding the sub_auth[] array, and offsetof(struct smb_ace, sid) is the ACE header, so the existing guards only guarantee the 8-byte SID base, i...

CVSS
8.1
EPSS
0.47%
38.1% percentile
CISA KEV
Not listed
Published
2026.07.19
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.47%
Technical severityCVSS 8.1

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix out-of-bounds read in smb_check_perm_dacl() The permission-check ACE walk in smb_check_perm_dacl() validates the ACE header size and caps sid.num_subauth at SID_MAX_SUB_AUTHORITIES, but it never checks that ace->size is actually large enough to contain num_subauth sub-authorities before compare_sids() dereferences them. CIFS_SID_BASE_SIZE covers the SID header up to but excluding the sub_auth[] array, and offsetof(struct smb_ace, sid) is the ACE header, so the existing guards only guarantee the 8-byte SID base, i...

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= 282cbbb476b9f35793452bc461934af4c7eca169 < c7488c85fd822959e9b5c22fbd9e7c8a21caf5e0, >= f20adc4ef7428bc485ee83fd1a592252fb87718b < 988c93d3bba066d8669143e6ec30bb2be9608d53, >= 325d4ac11f526cb8964cff14548ccf02d8c756d8 < 36599894fa8536fefdf1e296c0af71b8b7226859, >= 95e5aa3c3261da8c95b27d7aecf8ee39b9f86a4c < d5c81a095c86fe507c032d08f3a8cfc518444927, >= 90089584b2e25c4510b7b987387b4405f0673ece < 7627ff8c4f9919f14de562b0160ab4ec9d80b1f7, >= d07b26f39246a82399661936dd0c853983cfade7 < e36e35660adb9b8ef1435ac359151dda5f094c55, >= d07b26f39246a82399661936dd0c853983cfade7 < 1ef06004ed4bd6d3ed8c840d9d1a376b66d4935b, >= 151b1799861fde38087c08f613abc2843ef597b0, >= 5.15.210 < 5.15.212, >= 6.1.176 < 6.1.177, >= 6.6.140 < 6.6.144, >= 6.12.84 < 6.12.95, >= 6.18.25 < 6.18.38, >= 7.0.2 < 7.1, >= 7.1, >= 7.0.2 < 7.1.3, 6.1.176
Fixed versions
5.15.212, 6.6.144, 6.12.95, 6.18.38, 7.1.3

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel 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:L/UI:N/S:U/C:H/I:N/A:H
CWE
CWE-125