What’s Vulnerable › Vulnerabilities

CVE-2026-23742: Skipper arbitrary code execution through lua filters

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-01-16 · updated 2026-06-17
• Weakness: CWE-94

Description

Skipper is an HTTP router and reverse proxy for service composition. The default skipper configuration before 0.23.0 was -lua-sources=inline,file. The problem starts if untrusted users can create lua filters, because of -lua-sources=inline , for example through a Kubernetes Ingress resource. The configuration inline allows these user to create a script that is able to read the filesystem accessible to the skipper process and if the user has access to read the logs, they an read skipper secrets. This vulnerability is fixed in 0.23.0.

Affected products

• zalando skipper: before 0.23.0 — fixed in 0.23.0

How to fix

Upgrade to a fixed version: zalando skipper 0.23.0. Check the vendor advisory for mitigations.

References

• https://github.com/zalando/skipper/commit/0b52894570773b29e2f3c571b94b4211ef8fa714
• https://github.com/zalando/skipper/releases/tag/v0.23.0
• https://github.com/zalando/skipper/security/advisories/GHSA-cc8m-98fm-rc9g

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