CVE-2026-23742
CVE-2026-23742 is a high-severity vulnerability in Zalando Skipper with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-94.
Key facts
- Severity: High (CVSS 3.x base score 8.8)
- EPSS exploit prediction: 0% (38th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-2860
- Weakness: CWE-94
- Affected product: Zalando Skipper
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-23742?
- 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.
- How severe is CVE-2026-23742?
- CVE-2026-23742 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-23742 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-23742?
- CVE-2026-23742 affects Zalando Skipper. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-23742?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-23742 have an EU (EUVD) identifier?
- Yes. CVE-2026-23742 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-2860.
- When was CVE-2026-23742 published?
- CVE-2026-23742 was published on 2026-01-16 and last updated on 2026-06-17.
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
Affected products (1)
- cpe:2.3:a:zalando:skipper:*:*:*:*:*:*:*:*
More vulnerabilities in Zalando Skipper
- CVE-2022-38580 — Critical (CVSS 9.8): Zalando Skipper v0.13.236 is vulnerable to Server-Side Request Forgery (SSRF).
- CVE-2026-24470 — High (CVSS 8.1): Skipper is an HTTP router and reverse proxy for service composition. Prior to version 0.24.0, when running Skipper as…
- CVE-2022-34296 — High (CVSS 7.5): In Zalando Skipper before 0.13.218, a query predicate could be bypassed via a prepared request.
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