opa-envoy-plugin has an Authorization Bypass via Double-Slash Path Misinterpretation in input.parsed_path

Exploitation

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

CVSS 4.0

7.1 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H · score source

EPSS

• CVE-2026-26205: 0.53% estimated exploitation activity in the next 30 days; percentile 45.11 (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.

A security vulnerability has been discovered in how the input.parsedpath field is constructed. HTTP request paths are treated as full URIs when parsed; interpreting leading path segments prefixed with double slashes (//) as authority components, and therefore dropping them from the parsed path. This creates a path interpretation mismatch between authorization policies and backend servers, enabling attackers to bypass access controls by crafting requests where the authorization filter evaluates a different path than the one ultimately served. Attack example HTTP request: Policy sees: The leading //admin path segment is interpreted as an authority component, and dropped from input.parsedpath field: Backend receives: //admin/users path, normalized to /admin/users. Affected Request Pattern Examples | Request path | input.parsedpath | input.attributes.request.http.path | Discrepancy | | - | - | - | - | | / | [""] | / | ✅ None | | //foo | [""] | //foo| ❌ Mismatch | | /admin | ["admin"] |…

Published by the source

18 Feb 2026, 15:25 UTC

Last modified by the source

19 Feb 2026, 21:56 UTC

Source last checked

26 Oct 2026, 15:14 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-9f29-v6mm-pw6w

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# Patch Next advisory brief: CVE-2026-26205

Advisory: opa-envoy-plugin has an Authorization Bypass via Double-Slash Path Misinterpretation in input.parsed_path
IDs: CVE-2026-26205, GHSA-9f29-v6mm-pw6w
Record: https://patchnext.com/advisories/cve-2026-26205 (revision 1, source checked 26 Oct 2026, 15:14 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/open-policy-agent/opa-envoy-plugin 1.13.2-envoy-2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/open-policy-agent/opa-envoy-plugin: affected <= 1.13.1-envoy; fixed in 1.13.2-envoy-2

## Suggested inspection (read-only)
- Go github.com/open-policy-agent/opa-envoy-plugin: 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/open-policy-agent/opa-envoy-plugin.
- 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-9f29-v6mm-pw6w (GitHub-reviewed advisory GHSA-9f29-v6mm-pw6w lists affected ranges: Go github.com/open-policy-agent/opa-envoy-plugin >=0 <=1.13.1-envoy)

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