Answer in brief
CVE-2026-52944 records a Medium severity (CVSS 5.5) vulnerability in ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <ef664475c1bf1a27d45dae6848ca9c9c4d86853f || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <3a9a0a1c38ef90788f5d7c4b29903c8b220f744a || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <3127a884525dc8ca4def73254bfcd3ccef0bf812 || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <c5ab11263e3c89aa7989afc5374ef7743e092fd0 || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <de9eb0b44fa9123170e6245b49638e0e453c10f8 || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <aef151bcfa494bfe983669de2726734b534adb73 || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <cc57232cae23c0df91b4a59d0f519141ce9b5b02 | ef664475c1bf1a27d45dae6848ca9c9c4d86853f, 3a9a0a1c38ef90788f5d7c4b29903c8b220f744a, 3127a884525dc8ca4def73254bfcd3ccef0bf812, c5ab11263e3c89aa7989afc5374ef7743e092fd0, de9eb0b44fa9123170e6245b49638e0e453c10f8, aef151bcfa494bfe983669de2726734b534adb73, cc57232cae23c0df91b4a59d0f519141ce9b5b02 |
| Linux/Linuxgeneric | 5.15 | Not reported |
Published upstream
Jun 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 24, 2026
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix FSCTL permission bypass by adding a permission check for FSCTL_SET_SPARSE FSCTL_SET_SPARSE in fsctl_set_sparse() modifies the file's sparse attribute and saves it through xattr without any permission checks. This exposes two issues: 1) A client on a read-only share can change the sparse attribute on files it opened, even though the share is read-only. Other FSCTL write operations already check test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE), but FSCTL_SET_SPARSE does not. 2) Even on writable shares, clients without FILE_WRITE_DATA or FILE_WRITE_ATTRIBUTES access should not modify the sparse attribute. Similar handle-level checks exist in other functions but are missing here. Add both share-level writable check and per-handle access check. Use goto out on error to avoid leaking file references.
Quoted source text, attributed separately from HOL analysis.