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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-10-21 · updated 2026-08-04
Weakness: CWE-203

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.

Affected products

Linux kernel: from 3.18 before 6.1.113; from 6.2 before 6.6.54; from 6.7 before 6.10.13; from 6.11 before 6.11.2 — fixed in 6.1.113, 6.10.13, 6.11.2, 6.6.54

How to fix

Upgrade to a fixed version: Linux kernel 6.1.113, 6.10.13, 6.11.2, 6.6.54. Check the vendor advisory for mitigations.

References

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