Zalando Skipper up to 0.27.36 opaAuthorizeRequestWithBody Filter openpolicyagent.go improper authorization

Summaryinfo

A vulnerability classified as problematic was found in Zalando Skipper up to 0.27.36. This affects the function opaAuthorizeRequestWithBody of the file filters/openpolicyagent/openpolicyagent.go of the component opaAuthorizeRequestWithBody Filter. Executing a manipulation can lead to improper authorization. The identification of this vulnerability is CVE-2026-86043. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in Zalando Skipper up to 0.27.36 and classified as problematic. This vulnerability affects the function opaAuthorizeRequestWithBody of the file filters/openpolicyagent/openpolicyagent.go of the component opaAuthorizeRequestWithBody Filter. The manipulation with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect integrity. CVE summarizes:

Skipper is an HTTP router and reverse proxy for service composition. Prior to version 0.27.37, the opaAuthorizeRequestWithBody filter can authorize an oversized request after Skipper truncates the body presented to Open Policy Agent because the input.truncated_body signal is derived from Content-Length rather than the actual read result. In filters/openpolicyagent/openpolicyagent.go, ExtractHttpBodyOptionally truncates bodies at maxBodyBytes, while filters/openpolicyagent/internal/envoy/skipperadapter.go copies the request headers without adding a Content-Length value that reflects the truncation. For an HTTP/1.1 request using Transfer-Encoding: chunked or an HTTP/2 request without Content-Length, a body-inspecting policy that follows the prior mitigation and permits input.truncated_body equal to false can evaluate only the truncated prefix, allow the request, and then forward the full oversized body to the protected upstream. This residual issue is distinct from CVE-2026-50197. This issue is fixed in version 0.27.37.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-86043 since 09/04/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1548.002.

Upgrading to version 0.27.37 eliminates this vulnerability.

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Productinfo

Vendor

• Zalando

Name

• Skipper

Version

• 0.27.0
• 0.27.1
• 0.27.2
• 0.27.3
• 0.27.4
• 0.27.5
• 0.27.6
• 0.27.7
• 0.27.8
• 0.27.9
• 0.27.10
• 0.27.11
• 0.27.12
• 0.27.13
• 0.27.14
• 0.27.15
• 0.27.16
• 0.27.17
• 0.27.18
• 0.27.19
• 0.27.20
• 0.27.21
• 0.27.22
• 0.27.23
• 0.27.24
• 0.27.25
• 0.27.26
• 0.27.27
• 0.27.28
• 0.27.29
• 0.27.30
• 0.27.31
• 0.27.32
• 0.27.33
• 0.27.34
• 0.27.35
• 0.27.36

Website

• Product: https://github.com/zalando/skipper/

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