Cyber Resilience

CVE-2026-24470

SSRF in Zalando Skipper ≤ 0.24.0

Published
26 January 2026
Modified
18 February 2026
Patch / advisory
CVSS Score v3.1 8.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
EPSS Score 0.0027 19th percentile
Risk Priority 58 floored blend · peak EPSS

Summary

CVE-2026-24470 is a high-severity Confused Deputy (CWE-441) vulnerability in Zalando Skipper. Its CVSS base score is 8.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Proxy (T1090); ranked at the 19th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-16 (Security and Privacy Attributes) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-24470 affects Skipper, an HTTP router and reverse proxy used for service composition, specifically when deployed as a Kubernetes Ingress controller in versions prior to 0.24.0. The vulnerability arises from the ability of authorized users to create Kubernetes Ingress resources paired with Services of type ExternalName, allowing them to craft routes that leverage Skipper's network access to reach otherwise internal services. This issue is classified under CWE-441 (Unintended Proxy or Intermediary) and CWE-918 (Server-Side Request Forgery), with a CVSS v3.1 base score of 8.1 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N), indicating high severity due to network accessibility, low complexity, and low privileges required.

An attacker with permissions to create Ingress and ExternalName Services—typically a low-privileged Kubernetes user—can exploit this by defining routes that proxy requests through Skipper to internal services not intended for external exposure. Successful exploitation enables unauthorized access to sensitive internal endpoints, potentially leading to high confidentiality and integrity impacts, such as data exfiltration or modification, without requiring user interaction or elevated privileges beyond resource creation.

Mitigation is addressed in Skipper version 0.24.0, which disables support for Kubernetes ExternalName Services by default. As a workaround prior to upgrading, operators can implement an allow list for ExternalName targets, including support for regular expressions, to restrict reachable services. Relevant advisories and the fixing commit are detailed in the Skipper GitHub security advisory (GHSA-mxxc-p822-2hx9) and commit a4c87ce029a58eb8e1c2c1f93049194a39cf6219, with additional context on ExternalName Services in Kubernetes documentation.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Skipper is an HTTP router and reverse proxy for service composition. Prior to version 0.24.0, when running Skipper as an Ingress controller, users with permissions to create an Ingress and a Service of type ExternalName can create routes that enable…

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them to use Skipper's network access to reach internal services. Version 0.24.0 disables Kubernetes ExternalName by default. As a workaround, developers can allow list targets of an ExternalName and allow list via regular expressions.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1090 Proxy Command And Control
Adversaries may use a connection proxy to direct network traffic between systems or act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure.
T1090.002 External Proxy Command And Control
Adversaries may use an external proxy to act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure.
T1090.001 Internal Proxy Command And Control
Adversaries may use an internal proxy to direct command and control traffic between two or more systems in a compromised environment.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-23742Same product: Zalando Skipper
CVE-2024-9870Shared CWE-441, CWE-918
CVE-2026-43910Shared CWE-441, CWE-918
CVE-2026-48522Shared CWE-441, CWE-918
CVE-2026-53931Shared CWE-441, CWE-918
CVE-2026-15183Shared CWE-441, CWE-918
CVE-2026-42043Shared CWE-441, CWE-918
CVE-2025-62718Shared CWE-441, CWE-918
CVE-2026-41365Shared CWE-441
CVE-2026-39906Shared CWE-441

Affected Assets

zalando
skipper
≤ 0.24.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V3.2.1
  • V3.5.1
  • V3.5.3
  • V3.5.8

Mitigating Controls (NIST 800-53 r5) AI

Associating and preserving security attributes such as original source identity prevents the loss of provenance that creates the confused deputy.

Information flow enforcement requires preserving and checking source attributes before forwarding requests outside the trust boundary.

Input validation directly stops untrusted URLs from being accepted and fetched without destination checks.

Access enforcement directly stops a component from acting on forwarded requests without verifying original source authorizations.

Boundary protection limits and inspects external forwarding, reducing the ability of an intermediary to act as an unintended proxy.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-04 mostly match
prevents

Proper conveyance and verification of original identity assertions directly prevents loss of request source when forwarding.

PR.PS-06 mostly match
prevents

Secure development practices directly include input validation and destination allow-listing that prevent SSRF.

DE.CM-09 partial match
prevents

Runtime monitoring of web applications and services can detect anomalous outbound requests indicative of SSRF.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover and record SSRF flaws in web applications.

PR.AA-05 partial match
prevents

Enforcing least-privilege authorizations on forwarded requests reduces confused-deputy abuse even if source identity is lost.

PR.IR-01 partial match
prevents

Network segmentation and egress controls can limit the damage from successful SSRF requests.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Access-control rules can limit which upstream identities may cause the product to act on their behalf, reducing confused-deputy risk.

prevents

Proper identity management ensures the original requester identity is preserved and validated before the product forwards requests.

degrades

Explicit access-rights assignment can restrict the product’s ability to act as an unintended proxy for external actors.

prevents

Operational threat data describing SSRF campaigns can be used to tighten outbound-request allow-lists and detection rules before attackers exploit them.

degrades

Privileged-access controls limit the rights the product may exercise on behalf of upstream callers, mitigating confused-deputy abuse.

degrades

Network-security controls can enforce source validation and prevent the product from blindly proxying traffic to external actors.

References