Network policy may be bypassed by some ICMP Echo Requests

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact Under certain conditions, ICMP Echo Request sent to a Cilium endpoint from an actor may bypass a network policy which disallows access from the actor to the endpoint, but allows from the endpoint to the actor. This does NOT apply to UDP and TCP traffic. The actor is either a pod or a cluster host or a remote host. The following conditions must be met: 1. Network policies have been created which: a) do not allow access from the actor to the endpoint; b) allow access from the endpoint to the actor and does not specify neither protocol nor port. 2. The endpoint has sent ICMP Echo Request to the actor with the ICMP identifier X. 3. The actor sends ICMP Echo Request to the endpoint with the same ICMP identifier X. 4. The request from the actor (3.) is sent before the Cilium's conntrack GC has removed the previously created conntrack entry (2.). Detailed description See https://github.com/cilium/cilium/commit/dfb008a9099c4da1e0fd964c899c43ee13280b0e (v1.9.x),…

Published by the source

21 May 2021, 14:32 UTC

Last modified by the source

9 Jan 2023, 05:05 UTC

Source last checked

26 Oct 2026, 14:54 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-c66w-hq56-4q97

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# Patch Next advisory brief: GHSA-c66w-hq56-4q97

Advisory: Network policy may be bypassed by some ICMP Echo Requests
IDs: GHSA-c66w-hq56-4q97
Record: https://patchnext.com/advisories/ghsa-c66w-hq56-4q97 (revision 1, source checked 26 Oct 2026, 14:54 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/cilium/cilium 1.9.5, 1.8.8, 1.7.15. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/cilium/cilium: affected >= 1.7.8, <= 1.7.14; >= 1.8.3, <= 1.8.7; >= 1.9.0, <= 1.9.4; fixed in 1.7.15, 1.8.8, 1.9.5

## Suggested inspection (read-only)
- Go github.com/cilium/cilium: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/cilium/cilium.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-c66w-hq56-4q97 (GitHub-reviewed advisory GHSA-c66w-hq56-4q97 lists affected ranges: Go github.com/cilium/cilium >=1.7.8 =1.8.3 =1.9.0 <=1.9.4)

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