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CVE-2026-86043 high CVSS 7.5

Authorization Flaw in github.com/zalando/skipper (CVE-2026-86043)

Summary

Vulnerability in github.com/zalando/skipper (CVE-2026-86043). Data can be tampered with by attackers. Exploitable via ExtractHttpBodyOptionally. Mitigation: upgrade to 0.27.37 or later.

Original description

The description as published by the source.

  • Affected component: filters/openpolicyagent/openpolicyagent.go → ExtractHttpBodyOptionally; combined with github.com/open-policy-agent/opa-envoy-plugin envoyauth/request.go → getParsedBody / checkIfHTTPBodyTruncated. Filter: opaAuthorizeRequestWithBody.
  • Affected versions: <= 0.27.33 (current HEAD e7d7014c). The truncated_body mitigation was introduced/recommended in v0.27.26 (advisory GHSA-8qqm-fp2q-v734) and remains bypassable.
  • Fix chain being audited: CVE-2026-50197 (GHSA-659f-rgp5-w4wf, commit 3152f3b0) → GHSA-8qqm-fp2q-v734 (docs + code, commit 1be950cd #4126, v0.27.26). This finding is the third, still-open variant.

Summary

Skipper's opaAuthorizeRequestWithBody filter authorizes requests by handing the (bounded) request body to Open Policy Agent. When a body exceeds -open-policy-agent-max-request-body-size (default 1 MB), Skipper truncates it before OPA sees it. Advisory GHSA-8qqm-fp2q-v734 established that deny-on-presence / body-inspecting policies fail OPEN on oversized bodies, and its remediation instructs policy authors to guard on input.attributes.request.http.truncated_body (implemented as the top-level input.truncated_body):

default allow := false
allow if {
    input.truncated_body == false
    # ... body-based conditions
}

That mitigation is itself incomplete. The truncated_body flag is computed by the OPA envoy plugin only when a content-length header is present. A request sen…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-86043 has been found in github.com/zalando/skipper.
Attackers can target a specific entry point like ExtractHttpBodyOptionally over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 7.5/10.
What to do: upgrade github.com/zalando/skipper to 0.27.37 or later.
If unsure, ask your IT team or search "github.com/zalando/skipper CVE-2026-86043" on the vendor's site.

CVE-2026-86043 (github.com/zalando/skipper) — CWE-863 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: ExtractHttpBodyOptionally / getParsedBody / checkIfHTTPBodyTruncated / opaAuthorizeRequestWithBody
Patched: 0.27.37 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

Incorrect authorization (CWE-863) exists in github.com/zalando/skipper. Attackers reach the vulnerable code path via ExtractHttpBodyOptionally without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of github.com/zalando/skipper. Attack surface: ExtractHttpBodyOptionally / getParsedBody / checkIfHTTPBodyTruncated / opaAuthorizeRequestWithBody.

🔥 Severity

Severity: High (CVSS 7.5/10). Data can be tampered with by attackers.

🔧 How to fix

Update to 0.27.37.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/zalando/skipper' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'github.com/zalando/skipper' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で github.com/zalando/skipper を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade github.com/zalando/skipper to 0.27.37

    ステージング環境で 0.27.37 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

go github.com/zalando/skipper
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.27.37"}]}]

References

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