Zalando Skipper up to 0.27.34 opaAuthorizeRequestWithBody Filter openpolicyagent.go improper authorization

Summaryinfo

A vulnerability has been found in Zalando Skipper up to 0.27.34 and classified as critical. Affected is the function opaAuthorizeRequestWithBody of the file filters/openpolicyagent/openpolicyagent.go of the component opaAuthorizeRequestWithBody Filter. The manipulation leads to improper authorization. This vulnerability is documented as CVE-2026-65838. The attack can be initiated remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Zalando Skipper up to 0.27.34. It has been rated as critical. This issue 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. Using CWE to declare the problem leads to 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. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-65838 since 07/23/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1548.002 for this issue.

Upgrading to version 0.27.35 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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

Website

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

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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