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| Vulnerability ID | VCID-beg3-c4a1-cfay |
| Aliases |
CVE-2026-31477
|
| Summary | In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix memory leaks and NULL deref in smb2_lock() smb2_lock() has three error handling issues after list_del() detaches smb_lock from lock_list at no_check_cl: 1) If vfs_lock_file() returns an unexpected error in the non-UNLOCK path, goto out leaks smb_lock and its flock because the out: handler only iterates lock_list and rollback_list, neither of which contains the detached smb_lock. 2) If vfs_lock_file() returns -ENOENT in the UNLOCK path, goto out leaks smb_lock and flock for the same reason. The error code returned to the dispatcher is also stale. 3) In the rollback path, smb_flock_init() can return NULL on allocation failure. The result is dereferenced unconditionally, causing a kernel NULL pointer dereference. Add a NULL check to prevent the crash and clean up the bookkeeping; the VFS lock itself cannot be rolled back without the allocation and will be released at file or connection teardown. Fix cases 1 and 2 by hoisting the locks_free_lock()/kfree() to before the if(!rc) check in the UNLOCK branch so all exit paths share one free site, and by freeing smb_lock and flock before goto out in the non-UNLOCK branch. Propagate the correct error code in both cases. Fix case 3 by wrapping the VFS unlock in an if(rlock) guard and adding a NULL check for locks_free_lock(rlock) in the shared cleanup. Found via call-graph analysis using sqry. |
| Status | Published |
| Exploitability | 0.5 |
| Weighted Severity | 2.8 |
| Risk | 1.4 |
| Affected and Fixed Packages | Package Details |
| CWE-476 | NULL Pointer Dereference |
| System | Score | Found at |
|---|---|---|
| epss | 0.00024 | https://api.first.org/data/v1/epss?cve=CVE-2026-31477 |
| epss | 0.00024 | https://api.first.org/data/v1/epss?cve=CVE-2026-31477 |
| epss | 0.0007 | https://api.first.org/data/v1/epss?cve=CVE-2026-31477 |
| epss | 0.0007 | https://api.first.org/data/v1/epss?cve=CVE-2026-31477 |
| cvssv3.1 | 5.5 | https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml |
| Attack Vector (AV) | Attack Complexity (AC) | Privileges Required (PR) | User Interaction (UI) | Scope (S) | Confidentiality Impact (C) | Integrity Impact (I) | Availability Impact (A) |
|---|---|---|---|---|---|---|---|
network adjacent_network local physical |
low high |
none low high |
none required |
unchanged changed |
high low none |
high low none |
high low none |
| Percentile | 0.06773 |
| EPSS Score | 0.00024 |
| Published At | April 24, 2026, 12:55 p.m. |
| Date | Actor | Action | Source | VulnerableCode Version |
|---|---|---|---|---|
| 2026-04-23T05:41:02.219113+00:00 | Debian Importer | Import | https://security-tracker.debian.org/tracker/data/json | 38.4.0 |