PT-2026-6430 · Go · Github.Com/Cert-Manager/Cert-Manager
Published
2026-02-02
·
Updated
2026-02-02
CVSS v3.1
5.9
Medium
| Vector | AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
Impact
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.
Patches
The vulnerability was introduced in cert-manager v1.18.0 and has been patched in cert-manager v1.19.3 and v1.18.5, which are the supported minor releases at the time of publishing.
cert-manager versions prior to v1.18.0 are unaffected.
Workarounds
- Using DNS-over-HTTPS reduces the risk of DNS traffic being intercepted and modified.
- Note that DNS-over-HTTPS does not prevent the risk of an attacker-controlled authoritative DNS server.
Resources
- Fix for cert-manager 1.18: https://github.com/cert-manager/cert-manager/pull/8467
- Fix for cert-manager 1.19: https://github.com/cert-manager/cert-manager/pull/8468
- Fix for master branch: https://github.com/cert-manager/cert-manager/pull/8469
Credits
Huge thanks to Oleh Konko (@1seal) for reporting the issue, providing a detailed PoC and an initial patch!
Fix
Improper Validation of Array Index
Incorrect Type Conversion or Cast
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Related Identifiers
Affected Products
Github.Com/Cert-Manager/Cert-Manager