Vulnerability Description
cert-manager adds certificates and certificate issuers as resource types in Kubernetes clusters, and simplifies the process of obtaining, renewing and using those certificates. In versions from 1.18.0 to before 1.18.5 and from 1.19.0 to before 1.19.3, the cert-manager-controller performs DNS lookups during ACME DNS-01 processing (for zone discovery and propagation self-checks). By default, these lookups use standard unencrypted DNS. An attacker who can intercept and modify DNS traffic from the cert-manager-controller pod can insert a crafted entry into cert-manager's DNS cache. Accessing this entry will trigger a panic, resulting in denial‑of‑service (DoS) of the cert-manager controller. The issue can also be exploited if the authoritative DNS server for the domain being validated is controlled by a malicious actor. This issue has been patched in versions 1.18.5 and 1.19.3.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Cert-Manager | Cert-Manager | >= 1.18.0, < 1.18.5 |
Related Weaknesses (CWE)
References
- https://github.com/cert-manager/cert-manager/commit/409fc24e539711a07aae45ed45abPatch
- https://github.com/cert-manager/cert-manager/commit/9a73a0b3853035827edd37ac463ePatch
- https://github.com/cert-manager/cert-manager/commit/d4faed26ae12115cceb807cdc125Patch
- https://github.com/cert-manager/cert-manager/pull/8467Issue TrackingPatch
- https://github.com/cert-manager/cert-manager/pull/8468Issue TrackingPatch
- https://github.com/cert-manager/cert-manager/pull/8469Issue TrackingPatch
- https://github.com/cert-manager/cert-manager/security/advisories/GHSA-gx3x-vq4p-MitigationPatchVendor Advisory
FAQ
What is CVE-2026-25518?
CVE-2026-25518 is a vulnerability with a CVSS score of 5.9 (MEDIUM). cert-manager adds certificates and certificate issuers as resource types in Kubernetes clusters, and simplifies the process of obtaining, renewing and using those certificates. In versions from 1.18.0...
How severe is CVE-2026-25518?
CVE-2026-25518 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-25518?
Check the references section above for vendor advisories and patch information. Affected products include: Cert-Manager Cert-Manager.