# CVE-2025-38323: net: atm: add lec_mutex

> A use-after-free vulnerability in the Linux kernel's ATM LANE driver allows local attackers to potentially execute code or escalate privileges via a race condition.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Jul 2025
- **Updated:** 11 May 2026
- **Also known as:** AZL-64938, BELL-CVE-2025-38323, DEBIAN-CVE-2025-38323, GHSA-q8ww-99pm-fjf2, ROOT-OS-DEBIAN-11-CVE-2025-38323, ROOT-OS-DEBIAN-12-CVE-2025-38323, ROOT-OS-UBUNTU-2204-CVE-2025-38323, ROOT-OS-UBUNTU-2404-CVE-2025-38323, UBUNTU-CVE-2025-38323

## What is CVE-2025-38323?

CVE-2025-38323 is a high-severity use after free vulnerability in Debian Debian Linux, published on 10 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

net: atm: add lec_mutex

syzbot found its way in net/atm/lec.c, and found an error path
in lecd_attach() could leave a dangling pointer in dev_lec[].

Add a mutex to protect dev_lecp[] uses from lecd_attach(),
lec_vcc_attach() and lec_mcast_attach().

Following patch will use this mutex for /proc/net/atm/lec.

BUG: KASAN: slab-use-after-free in lecd_attach net/atm/lec.c:751 [inline]
BUG: KASAN: slab-use-after-free in lane_ioctl+0x2224/0x23e0 net/atm/lec.c:1008
Read of size 8 at addr ffff88807c7b8e68 by task syz.1.17/6142

CPU: 1 UID: 0 PID: 6142 Comm: syz.1.17 Not tainted 6.16.0-rc1-syzkaller-00239-g08215f5486ec #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
  __dump_stack lib/dump_stack.c:94 [inline]
  dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
  print_address_description mm/kasan/report.c:408 [inline]
  print_report+0xcd/0x680 mm/kasan/report.c:521
  kasan_report+0xe0/0x110 mm/kasan/report.c:634
  lecd_attach net/atm/lec.c:751 [inline]
  lane_ioctl+0x2224/0x23e0 net/atm/lec.c:1008
  do_vcc_ioctl+0x12c/0x930 net/atm/ioctl.c:159
  sock_do_ioctl+0x118/0x280 net/socket.c:1190
  sock_ioctl+0x227/0x6b0 net/socket.c:1311
  vfs_ioctl fs/ioctl.c:51 [inline]
  __do_sys_ioctl fs/ioctl.c:907 [inline]
  __se_sys_ioctl fs/ioctl.c:893 [inline]
  __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
 </TASK>

Allocated by task 6132:
  kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
  kasan_save_track+0x14/0x30 mm/kasan/common.c:68
  poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
  __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
  kasan_kmalloc include/linux/kasan.h:260 [inline]
  __do_kmalloc_node mm/slub.c:4328 [inline]
  __kvmalloc_node_noprof+0x27b/0x620 mm/slub.c:5015
  alloc_netdev_mqs+0xd2/0x1570 net/core/dev.c:11711
  lecd_attach net/atm/lec.c:737 [inline]
  lane_ioctl+0x17db/0x23e0 net/atm/lec.c:1008
  do_vcc_ioctl+0x12c/0x930 net/atm/ioctl.c:159
  sock_do_ioctl+0x118/0x280 net/socket.c:1190
  sock_ioctl+0x227/0x6b0 net/socket.c:1311
  vfs_ioctl fs/ioctl.c:51 [inline]
  __do_sys_ioctl fs/ioctl.c:907 [inline]
  __se_sys_ioctl fs/ioctl.c:893 [inline]
  __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893
  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
  do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6132:
  kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
  kasan_save_track+0x14/0x30 mm/kasan/common.c:68
  kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
  poison_slab_object mm/kasan/common.c:247 [inline]
  __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
  kasan_slab_free include/linux/kasan.h:233 [inline]
  slab_free_hook mm/slub.c:2381 [inline]
  slab_free mm/slub.c:4643 [inline]
  kfree+0x2b4/0x4d0 mm/slub.c:4842
  free_netdev+0x6c5/0x910 net/core/dev.c:11892
  lecd_attach net/atm/lec.c:744 [inline]
  lane_ioctl+0x1ce8/0x23e0 net/atm/lec.c:1008
  do_vcc_ioctl+0x12c/0x930 net/atm/ioctl.c:159
  sock_do_ioctl+0x118/0x280 net/socket.c:1190
  sock_ioctl+0x227/0x6b0 net/socket.c:1311
  vfs_ioctl fs/ioctl.c:51 [inline]
  __do_sys_ioctl fs/ioctl.c:907 [inline]
  __se_sys_ioctl fs/ioctl.c:893 [inline]
  __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:893

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2025-38323?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38323?

Apply the vendor's patch.

## Is CVE-2025-38323 being exploited?

There is no known exploitation of CVE-2025-38323 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38323 and fix it if it is affected.

What it is: CVE-2025-38323 is a high-severity use after free vulnerability in Debian Debian Linux, published on 10 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-38323 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2025-38323/ (Markdown: https://insights.sbomify.com/CVE-2025-38323/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38323
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38323
- OSV: https://osv.dev/vulnerability/CVE-2025-38323

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38323/
Summaries are generated and may contain mistakes; the official description above is the record.