CVE-2026-86043

High

Description

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.

SeverityHigh
CVSS7.5
Exploit probability—
ProductGithub.com/zalando/skipper
PublishedSep 16, 2026
First seenSep 16, 2026

How to fix

Update
  • github.com/zalando/skipper0.27.37 or later

Affected products

ProductAffected versionsFixed in
github.com/zalando/skipperGov < 0.27.370.27.37

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CVE-2026-86043 · Github.com/zalando/skipper · Dark Radar