CVE-2026-99280
ksmbd: drain session procfs readers before dropping table references
What happened?
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: drain session procfs readers before dropping table references
Session registration failure and connection cleanup can drop the table reference while the per-session procfs entry is still accessible. If a reader holds the last remaining reference, its final put calls proc_remove() from its own callback and waits for that callback to finish.
Remove the procfs entry before dropping the table reference in the registration failure path. Queue sessions removed during connection cleanup and drain their procfs readers after releasing both session locks, then return their table references. Keep the global hash node unhashed while a session is queued so a concurrent unregister cannot drop the reference again.
Previous-session replacement also destroys the file table before the session is finally freed. Detach the idr under the lock used by procfs file counters, and report zero files after it has been detached. This prevents a reader from accessing the idr during or after its destruction.
Affected software and versions
| Software | Version information | Fixed version |
|---|---|---|
| LinuxLinux | affected: d7fd1f98607f2cd358e583f9548bdf0173090a86 to < 6789f0983f8e85ce3a5ed8c50fc05d613ead9c2c; affected: d7fd1f98607f2cd358e583f9548bdf0173090a86 to < 1c087cf7d5386c708d8984b263280b42b3daada0; affected: c99ea7855124ca1428a1e59c2b4590aaef34eacf; affected: 7.2.8 to < 7.3 | See vendor advisory |
| LinuxLinux | affected: 7.3; unaffected: 0 to < 7.3; unaffected: 7.3.2 to ≤ 7.3.*; unaffected: 7.4-rc1 to ≤ * | See vendor advisory |
Version information comes from the source record and can include unaffected products and exceptions. Distribution packages may contain backported fixes: an older upstream version alone does not prove a server is affected.
Is it being exploited?
This CVE was not listed in the CISA catalogue at our last retrieval. This does not establish that exploitation is absent.
How to respond
- Confirm the product, installed package version, and any configuration requirements in the vendor advisory.
- Follow the vendor’s remediation or workaround guidance in the references below. Structured fixed-version data is unavailable here; the publisher’s description may include a fix or workaround.
- Restart affected services if required, then verify the running version. Known exploitation may warrant investigation as well as patching.