ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size
Summary
| CVE | CVE-2026-90153 |
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| State | PUBLISHED |
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| Assigner | Linux |
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| Source Priority | CVE Program / NVD first with legacy fallback |
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| Published | 2026-09-17 17:17:08 UTC |
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| Updated | 2026-09-17 17:17:08 UTC |
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| Description | In the Linux kernel, the following vulnerability has been resolved:
ksmbd: bound smb_check_perm_dacl() ACE walks by DACL size
smb_check_perm_dacl() validates that the DACL fits inside the NT
security descriptor, but then bounds its two ACE walks by the
remaining NTSD length (acl_size) rather than the DACL's declared
size (pdacl_size).
When pdacl->size is smaller than the trailing NTSD buffer, bytes
after the declared DACL boundary - still inside the stored security
descriptor - are parsed as ACEs during access checks. A crafted
DACL can place an access-granting ACE beyond pdacl->size, and the
current code accepts it during SMB2_CREATE access validation, while
parse_dacl() and smb_inherit_dacl() stop at pdacl_size.
Bound both ACE walks by pdacl_size to match the DACL boundary
semantics used elsewhere in the server.
Validation:
- semantic KUnit harness shows the post-boundary ACE is selected
before the fix and rejected (EACCES) after it
- linux master (7.2-rc6), x86_64 |
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Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|
| CNA |
Linux |
Linux |
affected 8f0541186e9ad1b62accc9519cc2b7a7240272a7 a2051ffe452afad52f580b85a3fd8851933b1e7c git |
Not specified |
| CNA |
Linux |
Linux |
affected 8f0541186e9ad1b62accc9519cc2b7a7240272a7 a29f57a14c939586d84d7fd6a029bd1fd170098f git |
Not specified |
| CNA |
Linux |
Linux |
affected 8f0541186e9ad1b62accc9519cc2b7a7240272a7 a4a307d149327dad5fb25187e1b03cebd1b04de6 git |
Not specified |
| CNA |
Linux |
Linux |
affected 8f0541186e9ad1b62accc9519cc2b7a7240272a7 8e4f75e979c1d9a51b0a48ac33d0cfd5f039ec67 git |
Not specified |
| CNA |
Linux |
Linux |
affected 8f0541186e9ad1b62accc9519cc2b7a7240272a7 79decd88dd3f0d42e7fb0689b1a7853bfa302459 git |
Not specified |
| CNA |
Linux |
Linux |
affected cb69d4d6f709f87c94afa28ae64c501576692171 git |
Not specified |
| CNA |
Linux |
Linux |
affected 6e8f4abf584253cbaa596ea4ad13110cf61cd4c9 git |
Not specified |
| CNA |
Linux |
Linux |
affected 8e33102309bd6839b2e2e158f93a7b378cb4655d git |
Not specified |
| CNA |
Linux |
Linux |
affected 5.15.62 5.16 semver |
Not specified |
| CNA |
Linux |
Linux |
affected 5.18.18 5.19 semver |
Not specified |
| CNA |
Linux |
Linux |
affected 5.19.2 5.20 semver |
Not specified |
| CNA |
Linux |
Linux |
affected 6.0 |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.0 semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.6.157 6.6.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.12.110 6.12.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.18.52 6.18.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.2.6 7.2.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.3-rc1 * original_commit_for_fix |
Not specified |
References
| Reference | Source | Link | Tags |
|---|
| git.kernel.org/stable/c/a4a307d149327dad5fb25187e1b03cebd1b04de6 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/79decd88dd3f0d42e7fb0689b1a7853bfa302459 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/a29f57a14c939586d84d7fd6a029bd1fd170098f |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/8e4f75e979c1d9a51b0a48ac33d0cfd5f039ec67 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/a2051ffe452afad52f580b85a3fd8851933b1e7c |
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.