EnvoyApplication · Envoyproxy

CVE-2021-39206

HIGH · 8.6 CVSS v3.1 Published 2021-09-09
Fix available
A fix is available. Upgrade to 0.14.8 / 1.16.5 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Pomerium is an open source identity-aware access proxy. Envoy, which Pomerium is based on, contains two authorization related vulnerabilities CVE-2021-32777 and CVE-2021-32779. This may lead to incorrect routing or authorization policy decisions. With specially crafted requests, incorrect authorization or routing decisions may be made by Pomerium. Pomerium v0.14.8 and v0.15.1 contain an upgraded envoy binary with these vulnerabilities patched. This issue can only be triggered when using path prefix based policy. Removing any such policies should provide mitigation.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Pomerium, an identity-aware access proxy built on Envoy, contains two underlying Envoy vulnerabilities (CVE-2021-32777 and CVE-2021-32779) that can cause incorrect routing or authorization policy decisions when specially crafted requests are sent. This only affects deployments using path prefix based policies, where an attacker could potentially bypass authorization or cause incorrect routing.

MitigationRemove any path prefix based policies from the Pomerium configuration, or upgrade to Pomerium v0.14.8 or v0.15.1 which contain the patched Envoy binary.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
EnvoyApplication
Affected:< 1.16.5>= 1.17.0, < 1.17.4>= 1.18.0, < 1.18.4= 1.19.0
PomeriumApplication
Affected:>= 0.11.0, < 0.14.8= 0.15.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Pomerium version
    Run `pomerium --version` or inspect the running container/image tag to identify the installed Pomerium version
    Affected if Version is >= 0.11.0 and < 0.14.8, or equals 0.15.0 (vulnerable versions)
  2. Verify path prefix policies exist
    Review Pomerium configuration files (config.yaml or equivalent) and examine policy sections. Look for policies containing `prefix` or `path` matching rules in the route definitions
    Affected if Any policy uses path prefix matching (such as `prefix: /api` or `path_prefix: /admin`) in authorization or route definitions
  3. Confirm Envoy version inside Pomerium
    If accessing Pomerium logs or binary directly is possible, inspect the embedded Envoy version or check Pomerium release notes which bundle specific Envoy versions
    Affected if Embedded Envoy version is < 1.16.5, >= 1.17.0 and < 1.17.4, >= 1.18.0 and < 1.18.4, or equals 1.19.0

You are affected if you are running a vulnerable Pomerium version (0.11.0 through 0.14.8, or 0.15.0) AND have any path prefix based policies configured in your authorization or routing rules.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.14.8 / 1.16.5 / 1.17.4 or later
Fixed in 0.14.81.16.51.17.4
Interim mitigation

Remove any path prefix based policies from the Pomerium configuration, or upgrade to Pomerium v0.14.8 or v0.15.1 which contain the patched Envoy binary.

Recommended fix High confidence

Pomerium v0.14.8 or v0.15.1 (both contain fixed Envoy)

  1. Upgrade Pomerium to version 0.14.8 or 0.15.1, which contain the patched Envoy binary addressing CVE-2021-32777 and CVE-2021-32779
  2. After upgrading, verify that existing policies function correctly
  3. Alternatively (if upgrade is not immediately feasible), remove all path prefix based policies from your Pomerium configuration as a mitigation until upgrade can be performed
Caveat Review Pomerium release notes for v0.14.8 and v0.15.1 for any breaking changes between your current version and the target version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Envoy Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-39206 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data