CVE-2026-105769: Azure token theft in kaniko

CVE-2026-105769 affects kaniko, a popular container builder in Kubernetes and CI/CD. An unanchored regex in kaniko's ACR credential helper allows fake hostnames containing .azurecr.io (or .azurecr.cn, .de, .us) to be recognized as legitimate registries. When a Dockerfile references images from lookalike hosts, kaniko extracts Azure AD tokens and sends them to attacker endpoints. Token theft occurs during Dockerfile parsing, without requiring RUN or push.

CVSS score is 9.3 (critical severity). The risk is high because the stolen token can be used against Azure Resource Manager with all permissions of the build identity, and can be exchanged for credentials to any ACR the identity can access. The vulnerability affects kaniko versions before 1.25.20, which has been released as a fix. Social media reports consistent signals about the severity of the flaw and the availability of the patch.

Immediate action: upgrade kaniko to 1.25.20 or later. If your CI/CD uses kaniko with Azure, verify that all build nodes and container runners have the correct version. Do not use kaniko versions prior to 1.25.20 in environments processing unverified Dockerfiles or that combine public and private registries. Audit the Dockerfiles in your repositories to identify potentially malicious Dockerfiles that might invoke lookalike registries.