CVE-2023-6193
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 · uneditedquiche v. 0.15.0 through 0.19.0 was discovered to be vulnerable to unbounded queuing of path validation messages, which could lead to excessive resource consumption. QUIC path validation (RFC 9000 Section 8.2) requires that the recipient of a PATH_CHALLENGE frame responds by sending a PATH_RESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATH_CHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATH_RESPONSE frames can only be sent at the slower rate than they are received; leading to storage of path validation data in an unbounded queue. Quiche versions greater than 0.19.0 address this problem.
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 confidencequiche versions 0.15.0-0.19.0 fail to bound the queue for PATH_RESPONSE frames generated in response to received PATH_CHALLENGE frames per RFC 9000 Section 8.2. An unauthenticated remote attacker can send PATH_CHALLENGE frames while simultaneously restricting the victim's congestion window, causing PATH_RESPONSE frames to be generated faster than they can be transmitted, resulting in unbounded queue growth and excessive resource consumption.
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>= 0.15.0, <= 0.19.0CVSS 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
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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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Identify quiche library versionCheck the quiche version in use by examining Cargo.toml dependencies, package manager listings (pip show quiche, apt list --installed 2>/dev/null | grep quiche), or the quiche binary version flag if available (quiche --version)Affected if The installed version is 0.15.0 through 0.19.0 inclusive
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Confirm quiche deployment contextDetermine if quiche is deployed as a server-side QUIC implementation that processes incoming connections. Check running processes or service configurations for quiche-based servicesAffected if Quiche is running as a server handling QUIC connections and can receive PATH_CHLISTENGE frames from clients
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Check for PATH_CHALLENGE frame processingReview network traffic captures or QUIC protocol logs if available, looking for incoming PATH_CHALLENGE frames (type 0x1f) that would trigger PATH_RESPONSE generationAffected if The system processes incoming PATH_CHALLENGE frames from remote peers, which triggers the vulnerable code path
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Monitor for queue growth indicatorsIf accessible, monitor memory usage or internal queue metrics of the quiche process over time, particularly under load with multiple connectionsAffected if Unbounded queue growth is observed in the quiche connection state, indicating the vulnerability is being triggered
A system is affected if it runs any version of Cloudflare Quiche between 0.15.0 and 0.19.0 inclusive and processes QUIC connections that can receive PATH_CHALLENGE frames, enabling remote attackers to trigger excessive queue growth.
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 · scopedUpgrade quiche to a version greater than 0.19.0 to receive the fix that implements proper bounds on path validation message queuing.
0.19.1 or later
- Upgrade Quiche to version 0.19.1 or later (any version greater than 0.19.0 contains the fix)
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation2.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-6193 — 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-2023-6193 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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- 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
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