CVE-2026-25518
mediumpriority · track · 24EPSS 0.004 · 38 %ileDEEUUSEPSS · scored 2026-10-22
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (15)
Products and version ranges known to be affected.
- Red Hat Enterprise Linux 10.0 Extended Update Supportall versionscert_bundDEcpe:/o:redhat:enterprise_linux:10.0_extended_update_support
- Go github.com/cert-manager/cert-manager1.18.0 → 1.18.5osvUSpkg:golang/github.com/cert-manager/cert-manager
- Go github.com/cert-manager/cert-manager1.19.0 → 1.19.3osvUSpkg:golang/github.com/cert-manager/cert-manager
advisories (4)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-1007IBM App Connect Enterprise: Mehrere SchwachstellenDeutsch2026-04-07csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren, um einen Cross-Site Scripting Angriff durchzuführen, um einen SQL-Injection Angriff durchzuführen, und um beliebigen Programmcode auszuführen.
- GHSA-gx3x-vq4p-mhhvcert-manager-controller DoS via Specially Crafted DNS Response2026-02-02ghsa · osvUS
### 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!
- BIT-cert-manager-2026-25518cert-manager-controller DoS via Specially Crafted DNS Response2026-02-10vendor · osvUS
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.
- GO-2026-4399DoS in cert-manager-controller via Specially Crafted DNS Response in github.com/cert-manager/cert-manager2026-02-19vendor · osvUS
DoS in cert-manager-controller via Specially Crafted DNS Response in github.com/cert-manager/cert-manager
also known as (6)
Other names and identifiers for this entity.
- CNNVD-202602-552cnnvd
- EUVD-2026-5341enisa_euvd
- GHSA-gx3x-vq4p-mhhvenisa_euvd
- BIT-cert-manager-2026-25518osv
- GHSA-gx3x-vq4p-mhhvosv
- GO-2026-4399osv
sources
Which sources assert this record, and when.
references (22)
External citations — patches, advisories, analysis.
- https://cert-manager.io/Patchcnnvd
- https://github.com/cert-manager/cert-manager/commit/409fc24e539711a07aae45ed45abbe03dfdad2cccnnvd
- https://github.com/cert-manager/cert-manager/commit/9a73a0b3853035827edd37ac463e4803ba10327dcnnvd
- https://github.com/cert-manager/cert-manager/commit/d4faed26ae12115cceb807cdc12507ebc28980e2cnnvd
- https://github.com/cert-manager/cert-manager/pull/8467cnnvd
- https://github.com/cert-manager/cert-manager/pull/8468cnnvd
- https://github.com/cert-manager/cert-manager/pull/8469cnnvd
- https://github.com/cert-manager/cert-manager/security/advisories/GHSA-gx3x-vq4p-mhhvcnnvd
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