CVE-2026-53390

{"id": "CVE-2026-53390", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.1, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.2, "exploitabilityScore": 2.8}]}, "affected": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "affectedData": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "282cbbb476b9f35793452bc461934af4c7eca169", "lessThan": "c7488c85fd822959e9b5c22fbd9e7c8a21caf5e0", "versionType": "git"}, {"status": "affected", "version": "f20adc4ef7428bc485ee83fd1a592252fb87718b", "lessThan": "988c93d3bba066d8669143e6ec30bb2be9608d53", "versionType": "git"}, {"status": "affected", "version": "325d4ac11f526cb8964cff14548ccf02d8c756d8", "lessThan": "36599894fa8536fefdf1e296c0af71b8b7226859", "versionType": "git"}, {"status": "affected", "version": "95e5aa3c3261da8c95b27d7aecf8ee39b9f86a4c", "lessThan": "d5c81a095c86fe507c032d08f3a8cfc518444927", "versionType": "git"}, {"status": "affected", "version": "90089584b2e25c4510b7b987387b4405f0673ece", "lessThan": "7627ff8c4f9919f14de562b0160ab4ec9d80b1f7", "versionType": "git"}, {"status": "affected", "version": "d07b26f39246a82399661936dd0c853983cfade7", "lessThan": "e36e35660adb9b8ef1435ac359151dda5f094c55", "versionType": "git"}, {"status": "affected", "version": "d07b26f39246a82399661936dd0c853983cfade7", "lessThan": "1ef06004ed4bd6d3ed8c840d9d1a376b66d4935b", "versionType": "git"}, {"status": "affected", "version": "151b1799861fde38087c08f613abc2843ef597b0", "versionType": "git"}, {"status": "affected", "version": "5.15.210", "lessThan": "5.15.212", "versionType": "semver"}, {"status": "affected", "version": "6.1.176", "lessThan": "6.1.177", "versionType": "semver"}, {"status": "affected", "version": "6.6.140", "lessThan": "6.6.144", "versionType": "semver"}, {"status": "affected", "version": "6.12.84", "lessThan": "6.12.95", "versionType": "semver"}, {"status": "affected", "version": "6.18.25", "lessThan": "6.18.38", "versionType": "semver"}, {"status": "affected", "version": "7.0.2", "lessThan": "7.1", "versionType": "semver"}], "programFiles": ["fs/smb/server/smbacl.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "7.1"}, {"status": "unaffected", "version": "0", "lessThan": "7.1", "versionType": "semver"}, {"status": "unaffected", "version": "5.15.212", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.177", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.144", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.95", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.38", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.1.3", "versionType": "semver", "lessThanOrEqual": "7.1.*"}, {"status": "unaffected", "version": "7.2-rc1", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["fs/smb/server/smbacl.c"], "defaultStatus": "affected"}]}], "published": "2026-07-19T12:16:50.000", "references": [{"url": "https://git.kernel.org/stable/c/1ef06004ed4bd6d3ed8c840d9d1a376b66d4935b", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/36599894fa8536fefdf1e296c0af71b8b7226859", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/7627ff8c4f9919f14de562b0160ab4ec9d80b1f7", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/988c93d3bba066d8669143e6ec30bb2be9608d53", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/c7488c85fd822959e9b5c22fbd9e7c8a21caf5e0", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/d5c81a095c86fe507c032d08f3a8cfc518444927", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/e36e35660adb9b8ef1435ac359151dda5f094c55", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-125"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: fix out-of-bounds read in smb_check_perm_dacl()\n\nThe permission-check ACE walk in smb_check_perm_dacl() validates the ACE\nheader size and caps sid.num_subauth at SID_MAX_SUB_AUTHORITIES, but it\nnever checks that ace->size is actually large enough to contain\nnum_subauth sub-authorities before compare_sids() dereferences them.\n\nCIFS_SID_BASE_SIZE covers the SID header up to but excluding the\nsub_auth[] array, and offsetof(struct smb_ace, sid) is the ACE header,\nso the existing guards only guarantee the 8-byte SID base, i.e. zero\nsub-authorities. compare_sids() then reads ace->sid.sub_auth[i] for\ni < min(local_sid->num_subauth, ace->sid.num_subauth). The local\ncomparison SIDs (sid_everyone, sid_unix_NFS_mode, and the id_to_sid()\nresult) always have at least one sub-authority, and an attacker controls\nthe ACE revision and authority bytes (which lie within the in-bounds SID\nbase), so they can match one of those SIDs and force the sub_auth read.\n\nA crafted ACE with size == 16 and num_subauth >= 1 placed at the tail of\nthe security descriptor therefore causes a heap out-of-bounds read of up\nto SID_MAX_SUB_AUTHORITIES * sizeof(__le32) bytes past the pntsd\nallocation. The security descriptor is loaded by ksmbd_vfs_get_sd_xattr()\ninto a buffer sized exactly to the on-disk data (kzalloc(sd_size) in\nndr_decode_v4_ntacl()), so the read lands past the allocation. The\nmalformed descriptor can be stored verbatim via SMB2_SET_INFO (the DACL\nis not normalised before being written to the security.NTACL xattr) and\nthe read fires on a subsequent SMB2_CREATE access check, making this\nreachable by an authenticated client on a share that uses ACL xattrs.\n\nAdd the missing num_subauth-versus-ace_size check, mirroring the\nidentical guards already present in the sibling parsers parse_dacl() and\nsmb_inherit_dacl()."}], "lastModified": "2026-07-29T19:30:20.850", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "42434AE1-4361-420E-AC94-62114ADF9A54", "versionEndExcluding": "5.15.212", "versionStartIncluding": "5.15.210"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "86F30E4E-AC0B-4F7E-BD0D-8B4DFF40C8E5", "versionEndExcluding": "6.6.144", "versionStartIncluding": "6.6.140"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "18BFBAB5-F8BE-445D-A4DC-A598E4DD65C3", "versionEndExcluding": "6.12.95", "versionStartIncluding": "6.12.84"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "54268F52-8016-498C-94D4-7A78B8F35FEC", "versionEndExcluding": "6.18.38", "versionStartIncluding": "6.18.25"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "BF755E4C-E134-4585-AFB9-61E683441DD9", "versionEndExcluding": "7.1.3", "versionStartIncluding": "7.0.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.1.176:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "31ED607F-61AA-41F2-B79C-959EDFA61657"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}