CVE-2026-25518: cert-manager-controller DoS via Specially Crafted DNS Response
(updated )
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.
References
- github.com/advisories/GHSA-gx3x-vq4p-mhhv
- github.com/cert-manager/cert-manager
- github.com/cert-manager/cert-manager/commit/409fc24e539711a07aae45ed45abbe03dfdad2cc
- github.com/cert-manager/cert-manager/commit/9a73a0b3853035827edd37ac463e4803ba10327d
- github.com/cert-manager/cert-manager/commit/d4faed26ae12115cceb807cdc12507ebc28980e2
- github.com/cert-manager/cert-manager/pull/8467
- github.com/cert-manager/cert-manager/pull/8468
- github.com/cert-manager/cert-manager/pull/8469
- github.com/cert-manager/cert-manager/security/advisories/GHSA-gx3x-vq4p-mhhv
- nvd.nist.gov/vuln/detail/CVE-2026-25518
Code Behaviors & Features
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