CVE-2025-23028: Github.com/cilium/cilium Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-9m5p-c77c-f9j7
CVSS 5.3
CWE-770
Published
Advisory Summary

CVE-2025-23028 is a MODERATE (CVSS 5.3) denial of service vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting Github.com/cilium/cilium libraries in the Go ecosystem. The issue involves dos in cilium agent dns proxy from crafted dns responses. Remediation is available by upgrading affected packages to version 1.14.18, 1.15.12, 1.16.5.

CVE-2025-23028 at a Glance

CVE Identifier CVE-2025-23028
GHSA Identifier GHSA-9m5p-c77c-f9j7
Severity MODERATE
CVSS v3.1 Base Score 5.3
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product Github.com/cilium/cilium
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 5.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability Low (A:L)

How to Fix CVE-2025-23028

To remediate this vulnerability, upgrade all affected Github.com/cilium/cilium dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/cilium/cilium fixed: 1.14.18
Upgrade github.com/cilium/cilium to 1.14.18
github.com/cilium/cilium fixed: 1.15.12
Upgrade github.com/cilium/cilium to 1.15.12
github.com/cilium/cilium fixed: 1.16.5
Upgrade github.com/cilium/cilium to 1.16.5
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

inspect dependencies for github.com/cilium/cilium

How to Check if You Are Affected

To determine whether your application is affected by CVE-2025-23028, inspect your project dependencies for Github.com/cilium/cilium:

inspect dependencies for github.com/cilium/cilium

Analyze the terminal output to locate any version of Github.com/cilium/cilium in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.14.18), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In Github.com/cilium/cilium, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact 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. ### Patches This issue affects: - Cilium v1.14 between v1.14.0 and v1.14.17 inclusive - Cilium v1.15 between v1.15.0 and v1.15.11 inclusive - Cilium v1.16 between v1.16.0 and v1.16.4 inclusive This issue is fixed in: - Cilium v1.14.18 - Cilium v1.15.12 - Cilium v1.16.5 ### Workarounds There are no known workarounds to this issue. ### Acknowledgements The Cilium community has worked together with members of Isovalent and the Cisco Advanced Security Initiatives Group (ASIG) to prepare these mitigations. Special thanks to @kokelley-cisco for reporting this issue and @bimmlerd for the fix. ### For more information If you have any questions or comments about this advisory, please reach out on [Slack](https://docs.cilium.io/en/latest/community/community/#slack). If you think you have found a vulnerability affecting Cilium, we strongly encourage you to report it to our security mailing list at [security@cilium.io](mailto:security@cilium.io). This is a private mailing list for the Cilium security team, and your report will be treated as top priority.

CVE-2025-23028 Affected Github.com/cilium/cilium Versions

3 component(s)
Fixed Versions:
1.14.181.15.121.16.5
Product / Package Ecosystem Affected Versions Fixed Version
github.com/cilium/cilium
Go
≥ 1.14.0
< 1.14.18
1.14.18
github.com/cilium/cilium
Go
≥ 1.15.0
< 1.15.12
1.15.12
github.com/cilium/cilium
Go
≥ 1.16.0
< 1.16.5
1.16.5

References

Frequently Asked Questions

What is CVE-2025-23028?
CVE-2025-23028 is a security vulnerability in Github.com/cilium/cilium involving DoS in Cilium agent DNS proxy from crafted DNS responses under CWE-770: Allocation of Resources Without Limits or Throttling.
Which Github.com/cilium/cilium versions are affected?
Affected versions include releases prior to 1.14.18, 1.15.12, 1.16.5 across affected packages: github.com/cilium/cilium.
What version fixes CVE-2025-23028?
Upgrading to 1.14.18, 1.15.12, 1.16.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/cilium/cilium affected?
Yes, github.com/cilium/cilium is affected in releases prior to 1.14.18, 1.15.12, 1.16.5. Upgrade your dependency to 1.14.18, 1.15.12, 1.16.5 or later.
What is the CVSS score of CVE-2025-23028?
CVE-2025-23028 has a CVSS v3.1 base score of 5.3 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
What CWE is associated with CVE-2025-23028?
CVE-2025-23028 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check Go dependencies for CVE-2025-23028?
Run the dependency tree command: 'inspect dependencies for github.com/cilium/cilium'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9m5p-c77c-f9j7",
  "modified" : "2025-01-22T18:44:35Z",
  "published" : "2025-01-22T18:08:13Z",
  "aliases" : [ "CVE-2025-23028" ],
  "summary" : "DoS in Cilium agent DNS proxy from crafted DNS responses",
  "details" : "### Impact\n\nIn 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.\n\nFor 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.\n\n### Patches\n\nThis issue affects:\n\n- Cilium v1.14 between v1.14.0 and v1.14.17 inclusive\n- Cilium v1.15 between v1.15.0 and v1.15.11 inclusive\n- Cilium v1.16 between v1.16.0 and v1.16.4 inclusive\n\nThis issue is fixed in:\n\n- Cilium v1.14.18\n- Cilium v1.15.12\n- Cilium v1.16.5\n\n### Workarounds\n\nThere are no known workarounds to this issue.\n\n### Acknowledgements\n\nThe Cilium community has worked together with members of Isovalent and the Cisco Advanced Security Initiatives Group (ASIG) to prepare these mitigations. Special thanks to @kokelley-cisco for reporting this issue and @bimmlerd for the fix.\n\n### For more information\n\nIf you have any questions or comments about this advisory, please reach out on [Slack](https://docs.cilium.io/en/latest/community/community/#slack).\n\nIf you think you have found a vulnerability affecting Cilium, we strongly encourage you to report it to our security mailing list at [security@cilium.io](mailto:security@cilium.io). This is a private mailing list for the Cilium security team, and your report will be treated as top priority.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/cilium/cilium"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.14.0"
      }, {
        "fixed" : "1.14.18"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/cilium/cilium"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.15.0"
      }, {
        "fixed" : "1.15.12"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/cilium/cilium"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "1.16.0"
      }, {
        "fixed" : "1.16.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/cilium/cilium/security/advisories/GHSA-9m5p-c77c-f9j7"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-23028"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/cilium/cilium/pull/36252"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/cilium/cilium/commit/1971bc684b6b36703ebae0dd7539c623f988a257"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/cilium/cilium/commit/b1948e217a4212b81175d8bf763d0ef350fcc96c"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/cilium/cilium"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2025-01-22T18:08:13Z",
    "nvd_published_at" : "2025-01-22T17:15:13Z"
  }
}