GHSA-gx3x-vq4p-mhhv: github.com/cert-manager/cert-manager (CVE-2026-25518)

Package	Ecosystem	Affected	Fixed in
github.com/cert-manager/cert-manager	Go	>=1.18.0, <1.18.5 \|\| >=1.19.0, <1.19.3	1.18.5, 1.19.3

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

cert-manager-controller versions 1.18.0 to before 1.18.5 and 1.19.0 to before 1.19.3 (Go module github.com/cert-manager/cert-manager) are vulnerable to a denial of service. An attacker who can intercept or modify DNS traffic from the controller pod, or who controls the authoritative DNS server for the domain being validated, can insert a crafted DNS cache entry that causes a panic when accessed, crashing the controller. Upgrade to cert-manager 1.18.5 or 1.19.3. Using DNS-over-HTTPS reduces the interception risk but does not stop a malicious authoritative DNS server.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
5.9	Medium	3.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0037, the 31st percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:14 UTC First seen by agentprime
31 Oct 2026, 14:14 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.