Kubernetes
CVE-2026-25518
MEDIUM
GHSA-gx3x-vq4p-mhhv
Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from GitHub Advisory.
CVSS VectorGitHub Advisory
Lifecycle Timeline
3DescriptionGitHub Advisory
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.
AnalysisAI
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. A patch is available for immediate deployment.
Technical ContextAI
Classified as CWE-129 (Improper Validation of Array Index). Affects Cert-Manager. 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 c
RemediationAI
A vendor patch is available — apply it immediately. Restrict network access to the affected service where possible.
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View allVendor StatusVendor
SUSE
Severity: Medium| Product | Status |
|---|---|
| openSUSE Leap 15.6 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP5 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP6 | Fixed |
| openSUSE Leap 15.5 | Fixed |
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External POC / Exploit Code
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