# CVE-2025-38147: calipso: Don't call calipso functions for AF_INET sk.

> A local attacker can cause a kernel crash by triggering a null pointer dereference in the Calipso networking module via mismatched socket address families.

- **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:** 3 Jul 2025
- **Updated:** 11 May 2026
- **Also known as:** AZL-64526, BELL-CVE-2025-38147, DEBIAN-CVE-2025-38147, GHSA-j6gx-m3wp-hf2m, ROOT-OS-DEBIAN-11-CVE-2025-38147, ROOT-OS-DEBIAN-12-CVE-2025-38147, ROOT-OS-UBUNTU-2204-CVE-2025-38147, ROOT-OS-UBUNTU-2404-CVE-2025-38147, UBUNTU-CVE-2025-38147

## What is CVE-2025-38147?

CVE-2025-38147 is a medium-severity vulnerability in Debian Debian Linux, published on 3 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:

calipso: Don't call calipso functions for AF_INET sk.

syzkaller reported a null-ptr-deref in txopt_get(). [0]

The offset 0x70 was of struct ipv6_txoptions in struct ipv6_pinfo,
so struct ipv6_pinfo was NULL there.

However, this never happens for IPv6 sockets as inet_sk(sk)->pinet6
is always set in inet6_create(), meaning the socket was not IPv6 one.

The root cause is missing validation in netlbl_conn_setattr().

netlbl_conn_setattr() switches branches based on struct
sockaddr.sa_family, which is passed from userspace.  However,
netlbl_conn_setattr() does not check if the address family matches
the socket.

The syzkaller must have called connect() for an IPv6 address on
an IPv4 socket.

We have a proper validation in tcp_v[46]_connect(), but
security_socket_connect() is called in the earlier stage.

Let's copy the validation to netlbl_conn_setattr().

[0]:
Oops: general protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077]
CPU: 2 UID: 0 PID: 12928 Comm: syz.9.1677 Not tainted 6.12.0 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
RIP: 0010:txopt_get include/net/ipv6.h:390 [inline]
RIP: 0010:
Code: 02 00 00 49 8b ac 24 f8 02 00 00 e8 84 69 2a fd e8 ff 00 16 fd 48 8d 7d 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 53 02 00 00 48 8b 6d 70 48 85 ed 0f 84 ab 01 00
RSP: 0018:ffff88811b8afc48 EFLAGS: 00010212
RAX: dffffc0000000000 RBX: 1ffff11023715f8a RCX: ffffffff841ab00c
RDX: 000000000000000e RSI: ffffc90007d9e000 RDI: 0000000000000070
RBP: 0000000000000000 R08: ffffed1023715f9d R09: ffffed1023715f9e
R10: ffffed1023715f9d R11: 0000000000000003 R12: ffff888123075f00
R13: ffff88810245bd80 R14: ffff888113646780 R15: ffff888100578a80
FS:  00007f9019bd7640(0000) GS:ffff8882d2d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f901b927bac CR3: 0000000104788003 CR4: 0000000000770ef0
PKRU: 80000000
Call Trace:
 <TASK>
 calipso_sock_setattr+0x56/0x80 net/netlabel/netlabel_calipso.c:557
 netlbl_conn_setattr+0x10c/0x280 net/netlabel/netlabel_kapi.c:1177
 selinux_netlbl_socket_connect_helper+0xd3/0x1b0 security/selinux/netlabel.c:569
 selinux_netlbl_socket_connect_locked security/selinux/netlabel.c:597 [inline]
 selinux_netlbl_socket_connect+0xb6/0x100 security/selinux/netlabel.c:615
 selinux_socket_connect+0x5f/0x80 security/selinux/hooks.c:4931
 security_socket_connect+0x50/0xa0 security/security.c:4598
 __sys_connect_file+0xa4/0x190 net/socket.c:2067
 __sys_connect+0x12c/0x170 net/socket.c:2088
 __do_sys_connect net/socket.c:2098 [inline]
 __se_sys_connect net/socket.c:2095 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:2095
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xaa/0x1b0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f901b61a12d
Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 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 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9019bd6fa8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f901b925fa0 RCX: 00007f901b61a12d
RDX: 000000000000001c RSI: 0000200000000140 RDI: 0000000000000003
RBP: 00007f901b701505 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f901b5b62a0 R15: 00007f9019bb7000
 </TASK>
Modules linked in:

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2025-38147?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38147?

Apply the vendor's patch.

## Is CVE-2025-38147 being exploited?

There is no known exploitation of CVE-2025-38147 in the wild and no public exploit code.

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## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38147 and fix it if it is affected.

What it is: CVE-2025-38147 is a medium-severity vulnerability in Debian Debian Linux, published on 3 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-2025-38147 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-2025-38147/ (Markdown: https://insights.sbomify.com/CVE-2025-38147/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38147
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38147
- OSV: https://osv.dev/vulnerability/CVE-2025-38147

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38147/
Summaries are generated and may contain mistakes; the official description above is the record.