CVE-2020-25018
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 · uneditedEnvoy master between 2d69e30 and 3b5acb2 may fail to parse request URL that requires host canonicalization.
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 · moderate confidenceEnvoy proxy versions between commits 2d69e30 and 3b5acb2 contain a URL parsing flaw where requests requiring host canonicalization may fail to parse correctly, potentially allowing malformed or crafted URLs to bypass validation or cause parsing errors.
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>= 2d69e30, < 3b5acb2CVSS 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
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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 checksWork through these to decide whether this CVE applies to you.
-
Identify Envoy installation and versionRun 'envoy --version' or check the build metadata with 'envoy --version' to obtain the version string or commit SHAAffected if The version/commit falls between 2d69e30 and 3b5acb2 (inclusive of the lower bound, exclusive of the upper bound)
-
Confirm HTTP listener configurationReview Envoy configuration files (YAML/JSON) for any listener definitions with 'http' protocol or HTTP connection manager filtersAffected if HTTP listeners are defined, as URL parsing occurs at the HTTP layer for host canonicalization
-
Check for URL-based routing or host rewrite rulesInspect Envoy route configurations for use of 'host_rewrite', 'regex_rewrite', or path/host matchers that require URL canonicalizationAffected if Routes or virtual hosts are configured with host manipulation that triggers canonicalization logic
-
Review access logs for parsing anomaliesExamine Envoy access logs for 400 Bad Request errors related to URL/host parsing, particularly for requests with non-standard host headersAffected if Access logs show unusual 400 errors or failed requests that correlate with URL host canonicalization attempts
Envoy is affected if it is built from a commit between 2d69e30 and 3b5acb2 and handles HTTP traffic that requires host header canonicalization.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor data3b5acb2
Upgrade Envoy to a version beyond commit 3b5acb2 that contains the fix, or apply the specific commit patch addressing URL canonicalization parsing.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-25018 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-25018 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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