CVE-2024-23326
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 is a cloud-native, open source edge and service proxy. A theoretical request smuggling vulnerability exists through Envoy if a server can be tricked into adding an upgrade header into a response. Per RFC https://www.rfc-editor.org/rfc/rfc7230#section-6.7 a server sends 101 when switching protocols. Envoy incorrectly accepts a 200 response from a server when requesting a protocol upgrade, but 200 does not indicate protocol switch. This opens up the possibility of request smuggling through Envoy if the server can be tricked into adding the upgrade header to the response.
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 confidenceEnvoy incorrectly accepts a 200 response with an Upgrade header when requesting a protocol upgrade, when RFC 7230 section 6.7 specifies that only a 101 status code indicates successful protocol switching. This allows request smuggling through Envoy if an attacker can trick an upstream server into adding an Upgrade header to a 200 response.
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< 1.27.6>= 1.28.0, < 1.28.4>= 1.29.0, < 1.29.5>= 1.30.0, < 1.30.2CVSS 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
- High
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/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 checksWork through these to decide whether this CVE applies to you.
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Determine Envoy versionRun 'envoy --version' or check the binary metadata to identify the installed Envoy versionAffected if The version falls within < 1.27.6, >= 1.28.0 and < 1.28.4, >= 1.29.0 and < 1.29.5, or >= 1.30.0 and < 1.30.2
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Identify if HTTP upgrade capability is enabledReview the Envoy configuration file (static or dynamic) for 'upgrade_config' settings or any 'Upgrade' headers configured in the http_filters chainAffected if Upgrade handling is explicitly enabled in the Envoy listener or route configuration
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Check for upstream configurations that process responsesExamine Envoy upstream cluster configurations for any route or filter setups that may forward or process responses from backends that could add Upgrade headersAffected if Upstream configurations exist that could receive responses from servers capable of adding Upgrade headers to non-101 responses
You are affected if running a vulnerable Envoy version (as identified in step 1) AND the Envoy configuration has HTTP upgrade capabilities enabled (step 2) AND upstream responses could be manipulated to include Upgrade headers on non-101 status codes (step 3).
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.
dbcve · scoped1.27.61.28.41.29.5
Upgrade to the patched version of Envoy that properly validates that 101 is the only valid response for protocol upgrade requests, or implement strict validation of upstream responses to reject non-101 responses containing Upgrade headers.
1.30.2
- Upgrade Envoy to version 1.30.2, or if already on 1.29.x upgrade to 1.29.5, or if on 1.28.x upgrade to 1.28.4, or if on 1.27.x upgrade to 1.27.6
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2024-23326 — 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-2024-23326 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
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