smb: client: fix heap overflow in cifs_do_set_acl()
Summary
| CVE | CVE-2026-99110 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-28 11:17:30 UTC |
| Updated | 2026-10-31 13:17:55 UTC |
| Description | 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). |
Risk And Classification
Primary CVSS: v3.1 7 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.001840000 probability, percentile 0.079980000 (date 2026-10-30)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | Secondary | 7 | HIGH | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 7 | HIGH | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
LocalAttack Complexity
HighPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected dc1af4c4b4721abfa07b351063825acc7e69cc66 68652afb9b9adf70125971abee9b95341e042249 git | Not specified |
| CNA | Linux | Linux | affected dc1af4c4b4721abfa07b351063825acc7e69cc66 9312a00215602ba028495ef3fa00fb84af0478e0 git | Not specified |
| CNA | Linux | Linux | affected dc1af4c4b4721abfa07b351063825acc7e69cc66 d96f3365ce61c5f39602955af43c8174548dee98 git | Not specified |
| CNA | Linux | Linux | affected dc1af4c4b4721abfa07b351063825acc7e69cc66 596b4062e6c75bdd85a7f2b7f2087a872dc420ac git | Not specified |
| CNA | Linux | Linux | affected dc1af4c4b4721abfa07b351063825acc7e69cc66 1dac61e2c29d1a71784604b48cf3b1234a65ec29 git | Not specified |
| CNA | Linux | Linux | affected 6.2 | Not specified |
| CNA | Linux | Linux | unaffected 6.2 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.6.161 6.6.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.115 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.59 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.13 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.