CVE-2026-99110

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix heap overflow in cifs_do_set_acl() cifs_set_acl() validates ACL size using posix_acl_xattr_size(): 4 + (count * 8) // 4-byte header + 8 bytes per ACE cifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS wire format into the same buffer: 6 + (count * 10) // 6-byte header + 10 bytes per ACE An ACL that passes the xattr-based check in cifs_set_acl() can overflow the heap when posix_acl_to_cifs() writes the larger CIFS format. Validate the CIFS format size against the remaining buffer space and USHRT_MAX before converting--data_count is __u16, so sizes above USHRT_MAX truncate the on-wire packet length, causing the server to apply a partial ACL. Replace MaxDataCount = 1000 with min(CIFSMaxBufSize, USHRT_MAX).

CVSS v3 7.0 HIGH

7.0^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.0 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity HIGH

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29
https://git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac
https://git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249
https://git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0
https://git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98

Configurations

No configuration.

History

31 Oct 2026, 13:17

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.0

30 Oct 2026, 13:21

Type	Values Removed	Values Added
References		() https://git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249 - () https://git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0 -

28 Oct 2026, 11:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-28 11:17

Updated : 2026-10-31 13:17

NVD link : CVE-2026-99110

Mitre link : CVE-2026-99110

CVE.ORG link : CVE-2026-99110

JSON object : View

Products Affected

No product.

CWE

No CWE.

{"id": "CVE-2026-99110", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.0, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.0}]}, "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": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "lessThan": "68652afb9b9adf70125971abee9b95341e042249", "versionType": "git"}, {"status": "affected", "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "lessThan": "9312a00215602ba028495ef3fa00fb84af0478e0", "versionType": "git"}, {"status": "affected", "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "lessThan": "d96f3365ce61c5f39602955af43c8174548dee98", "versionType": "git"}, {"status": "affected", "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "lessThan": "596b4062e6c75bdd85a7f2b7f2087a872dc420ac", "versionType": "git"}, {"status": "affected", "version": "dc1af4c4b4721abfa07b351063825acc7e69cc66", "lessThan": "1dac61e2c29d1a71784604b48cf3b1234a65ec29", "versionType": "git"}], "programFiles": ["fs/smb/client/cifssmb.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "6.2"}, {"status": "unaffected", "version": "0", "lessThan": "6.2", "versionType": "semver"}, {"status": "unaffected", "version": "6.6.161", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.115", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.59", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.2.13", "versionType": "semver", "lessThanOrEqual": "7.2.*"}, {"status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["fs/smb/client/cifssmb.c"], "defaultStatus": "affected"}]}], "published": "2026-10-28T11:17:30.410", "references": [{"url": "https://git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Received", "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix heap overflow in cifs_do_set_acl()\n\ncifs_set_acl() validates ACL size using posix_acl_xattr_size():\n\n 4 + (count * 8) // 4-byte header + 8 bytes per ACE\n\ncifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS\nwire format into the same buffer:\n\n 6 + (count * 10) // 6-byte header + 10 bytes per ACE\n\nAn ACL that passes the xattr-based check in cifs_set_acl() can\noverflow the heap when posix_acl_to_cifs() writes the larger CIFS\nformat.\n\nValidate the CIFS format size against the remaining buffer space and\nUSHRT_MAX before converting--data_count is __u16, so sizes above\nUSHRT_MAX truncate the on-wire packet length, causing the server to\napply a partial ACL. Replace MaxDataCount = 1000 with\nmin(CIFSMaxBufSize, USHRT_MAX)."}], "lastModified": "2026-10-31T13:17:55.833", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}