# CVE-2024-36939: nfs: Handle error of rpc_proc_register() in nfs_net_init().

> A missing error check in the Linux kernel NFS module can cause a warning and potential crash when destroying network namespaces.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 30 May 2024
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2024-36939, DEBIAN-CVE-2024-36939, UBUNTU-CVE-2024-36939

## What is CVE-2024-36939?

CVE-2024-36939 is a medium-severity vulnerability in Debian Debian Linux, published on 30 May 2024. 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:

nfs: Handle error of rpc_proc_register() in nfs_net_init().

syzkaller reported a warning [0] triggered while destroying immature
netns.

rpc_proc_register() was called in init_nfs_fs(), but its error
has been ignored since at least the initial commit 1da177e4c3f4
("Linux-2.6.12-rc2").

Recently, commit d47151b79e32 ("nfs: expose /proc/net/sunrpc/nfs
in net namespaces") converted the procfs to per-netns and made
the problem more visible.

Even when rpc_proc_register() fails, nfs_net_init() could succeed,
and thus nfs_net_exit() will be called while destroying the netns.

Then, remove_proc_entry() will be called for non-existing proc
directory and trigger the warning below.

Let's handle the error of rpc_proc_register() properly in nfs_net_init().

[0]:
name 'nfs'
WARNING: CPU: 1 PID: 1710 at fs/proc/generic.c:711 remove_proc_entry+0x1bb/0x2d0 fs/proc/generic.c:711
Modules linked in:
CPU: 1 PID: 1710 Comm: syz-executor.2 Not tainted 6.8.0-12822-gcd51db110a7e #12
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
RIP: 0010:remove_proc_entry+0x1bb/0x2d0 fs/proc/generic.c:711
Code: 41 5d 41 5e c3 e8 85 09 b5 ff 48 c7 c7 88 58 64 86 e8 09 0e 71 02 e8 74 09 b5 ff 4c 89 e6 48 c7 c7 de 1b 80 84 e8 c5 ad 97 ff <0f> 0b eb b1 e8 5c 09 b5 ff 48 c7 c7 88 58 64 86 e8 e0 0d 71 02 eb
RSP: 0018:ffffc9000c6d7ce0 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff8880422b8b00 RCX: ffffffff8110503c
RDX: ffff888030652f00 RSI: ffffffff81105045 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffffffff81bb62cb R12: ffffffff84807ffc
R13: ffff88804ad6fcc0 R14: ffffffff84807ffc R15: ffffffff85741ff8
FS:  00007f30cfba8640(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff51afe8000 CR3: 000000005a60a005 CR4: 0000000000770ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 <TASK>
 rpc_proc_unregister+0x64/0x70 net/sunrpc/stats.c:310
 nfs_net_exit+0x1c/0x30 fs/nfs/inode.c:2438
 ops_exit_list+0x62/0xb0 net/core/net_namespace.c:170
 setup_net+0x46c/0x660 net/core/net_namespace.c:372
 copy_net_ns+0x244/0x590 net/core/net_namespace.c:505
 create_new_namespaces+0x2ed/0x770 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xae/0x160 kernel/nsproxy.c:228
 ksys_unshare+0x342/0x760 kernel/fork.c:3322
 __do_sys_unshare kernel/fork.c:3393 [inline]
 __se_sys_unshare kernel/fork.c:3391 [inline]
 __x64_sys_unshare+0x1f/0x30 kernel/fork.c:3391
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x4f/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x46/0x4e
RIP: 0033:0x7f30d0febe5d
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 9f 1b 00 f7 d8 64 89 01 48
RSP: 002b:00007f30cfba7cc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 00000000004bbf80 RCX: 00007f30d0febe5d
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006c020600
RBP: 00000000004bbf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002
R13: 000000000000000b R14: 00007f30d104c530 R15: 0000000000000000
 </TASK>

## Which versions are affected by CVE-2024-36939?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2024-36939?

Apply the vendor's patch.

## Is CVE-2024-36939 being exploited?

There is no known exploitation of CVE-2024-36939 in the wild and no public exploit code.

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## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-36939 and fix it if it is affected.

What it is: CVE-2024-36939 is a medium-severity vulnerability in Debian Debian Linux, published on 30 May 2024. 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-2024-36939 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-2024-36939/ (Markdown: https://insights.sbomify.com/CVE-2024-36939/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-36939
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-36939
- OSV: https://osv.dev/vulnerability/CVE-2024-36939

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-36939/
Summaries are generated and may contain mistakes; the official description above is the record.