---
id: CVE-2026-65838
title: Skipper is an HTTP router and reverse proxy for service composition
summary: >-
  Skipper is an HTTP router and reverse proxy for service composition. Prior to
  0.27.35, the opaAuthorizeRequestWithBody filter in
  filters/openpolicyagent/openpolicyagent.go can allow an oversized declared
  Content-Length request to bypass …
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N'
cwe:
  - CWE-754
  - CWE-444
vendor: zalando
product: skipper
affected:
  - skipper < 0.27.35
published: '2026-09-14'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T13:42:48.383'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-65838'
references:
  - url: >-
      https://github.com/zalando/skipper/commit/2cfceabaa6ff0af65b312dcb9bcbe84691b9d507
    label: security-advisories@github.com
  - url: 'https://github.com/zalando/skipper/releases/tag/v0.27.35'
    label: security-advisories@github.com
  - url: 'https://github.com/zalando/skipper/security/advisories/GHSA-8qqm-fp2q-v734'
    label: security-advisories@github.com
  - url: 'https://github.com/zalando/skipper'
  - url: 'https://github.com/zalando/skipper/releases/tag/v0.27.26'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-65838'
  - url: 'https://github.com/advisories/GHSA-8qqm-fp2q-v734'
tags:
  - nvd
  - cve.org
  - osv
  - go
  - ghsa
epss: 0.00464
epssPercentile: 0.37563
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-15T13:26:56.403629Z'
ingestedAt: '2026-09-14T20:14:21.147Z'
aliases:
  - GHSA-8qqm-fp2q-v734
  - GO-2026-6019
ecosystem: go
patched:
  - github.com/zalando/skipper 0.27.26
---

## Overview

Skipper is an HTTP router and reverse proxy for service composition. Prior to 0.27.35, the opaAuthorizeRequestWithBody filter in filters/openpolicyagent/openpolicyagent.go can allow an oversized declared Content-Length request to bypass a deny-on-presence Rego policy because ExtractHttpBodyOptionally leaves OPA with an empty parsed_body while forwarding the complete request body upstream. This incomplete remediation of CVE-2026-50197 affects deployments that authorize request-body content and exceed -open-policy-agent-max-request-body-size, which defaults to 1 MB. Policy logic that does not reject input.attributes.request.http.truncated_body can therefore fail open and permit a forbidden payload to reach the protected service, while small bodies and the previously fixed chunked-body case are evaluated normally. This issue is fixed in version 0.27.35.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-65838)

Affected packages:

- `github.com/zalando/skipper < 0.27.26`

Patched in:

- `github.com/zalando/skipper 0.27.26`

Source: https://osv.dev/vulnerability/GHSA-8qqm-fp2q-v734