CVE-2026-25518
MEDIUM
GHSA-gx3x-vq4p-mhhv
CVSS Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
3Tags
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.
Analysis
Denial-of-service in cert-manager versions 1.18.0-1.18.4 and 1.19.0-1.19.2 allows network-adjacent attackers to crash the controller by poisoning DNS cache entries during ACME DNS-01 validation through unencrypted DNS traffic interception. An attacker positioned to intercept DNS queries from the cert-manager pod can inject malicious DNS responses that trigger a panic in the controller, disrupting certificate management operations in affected Kubernetes clusters. …
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Remediation
Within 30 days: Identify affected systems running versions from 1.18.0 to and apply vendor patches as part of regular patch cycle. Vendor patch is available.
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