Skipper: opaAuthorizeRequestWithBody filter bypasses OPA policy on Transfer-Encoding — chunked / HTTP/2 requests

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.7 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N/E:U/RL:O

EPSS

• CVE-2026-50197: 0.51% estimated exploitation activity in the next 30 days; percentile 43.80 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary zalando/skipper's OpenPolicyAgent integration silently bypasses request-body inspection on HTTP/1.1 Transfer-Encoding: chunked and HTTP/2 requests that omit the content-length pseudo-header. When the opaAuthorizeRequestWithBody filter is configured, the OpenPolicyAgentInstance.ExtractHttpBodyOptionally helper produces an empty rawbody for any request whose Content-Length header is missing, while the underlying chunked body still flows through to the upstream service. Rego policies that gate on input.parsedbody (e.g. "deny when a forbidden field is present") evaluate against an empty document, treat the forbidden field as absent, and authorize the request. The upstream handler then receives the full attacker payload that the policy intended to block. Affected versions github.com/zalando/skipper versions <= v0.26.8 (the latest release on 2026-05-26, current master 4eed47ff). The vulnerable helper and gate have lived in filters/openpolicyagent/openpolicyagent.go since the…

Published by the source

8 Jul 2026, 20:23 UTC

Last modified by the source

8 Jul 2026, 20:23 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-659f-rgp5-w4wf

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# Patch Next advisory brief: CVE-2026-50197

Advisory: Skipper: opaAuthorizeRequestWithBody filter bypasses OPA policy on Transfer-Encoding — chunked / HTTP/2 requests
IDs: CVE-2026-50197, GHSA-659f-rgp5-w4wf
Record: https://patchnext.com/advisories/cve-2026-50197 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/zalando/skipper 0.26.10. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/zalando/skipper: affected < 0.26.10; fixed in 0.26.10

## Suggested inspection (read-only)
- Go github.com/zalando/skipper: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/zalando/skipper.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-659f-rgp5-w4wf (GitHub-reviewed advisory GHSA-659f-rgp5-w4wf lists affected ranges: Go github.com/zalando/skipper >=0 <0.26.10)

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