# CVE-2025-37777: ksmbd: fix use-after-free in __smb2_lease_break_noti()

> A use-after-free vulnerability in the Linux kernel's ksmbd module allows attackers to potentially execute code or escalate privileges via asynchronous lease break notifications.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 May 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-37777, DEBIAN-CVE-2025-37777, GHSA-4748-h423-7xq4, ROOT-OS-DEBIAN-12-CVE-2025-37777, ROOT-OS-UBUNTU-2204-CVE-2025-37777, ROOT-OS-UBUNTU-2404-CVE-2025-37777, UBUNTU-CVE-2025-37777

## What is CVE-2025-37777?

CVE-2025-37777 is a high-severity use after free vulnerability in Linux kernel, published on 1 May 2025. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix use-after-free in __smb2_lease_break_noti()

Move tcp_transport free to ksmbd_conn_free. If ksmbd connection is
referenced when ksmbd server thread terminates, It will not be freed,
but conn->tcp_transport is freed. __smb2_lease_break_noti can be performed
asynchronously when the connection is disconnected. __smb2_lease_break_noti
calls ksmbd_conn_write, which can cause use-after-free
when conn->ksmbd_transport is already freed.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2025-37777?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-37777?

Apply the vendor's patch.

## Is CVE-2025-37777 being exploited?

There is no known exploitation of CVE-2025-37777 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-37777 and fix it if it is affected.

What it is: CVE-2025-37777 is a high-severity use after free vulnerability in Linux kernel, published on 1 May 2025. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-37777 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-37777/ (Markdown: https://insights.sbomify.com/CVE-2025-37777/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-37777
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-37777
- OSV: https://osv.dev/vulnerability/CVE-2025-37777

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-37777/
Summaries are generated and may contain mistakes; the official description above is the record.