CVE-2023-6193 Unbounded queuing of path validation messages in cloudflare-quiche
An unauthenticated remote attacker can cause excessive resource consumption and denial of service by exploiting unbounded queuing of path validation messages in the quiche library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-6193?
CVE-2023-6193 is a medium-severity denial of service vulnerability in Cloudflare quiche, published on 12 Dec 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
quiche 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.
Weakness: CWE-400
Which versions are affected by CVE-2023-6193?
2 open source packages ship an affected version, including quiche. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
quiche crates.io | From 0.15.0 | 0.19.1 |
quiche crates.io | From 0.15.0 | 0.19.1 |
Products include Cloudflare Quiche.
How do I fix CVE-2023-6193?
Upgrade quiche to 0.19.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-6193 being exploited?
There is no known exploitation of CVE-2023-6193 in the wild and no public exploit code.
Other vulnerabilities in Cloudflare quiche
- CVE-2025-7054 Infinite loop triggered by connection ID retirement
- CVE-2026-12523 Resource exhaustion in quiche HTTP/3 and QPACK layers
- CVE-2025-4821 Incorrect congestion window growth by invalid ACK ranges
- CVE-2024-1765 Unlimited resource allocation by QUIC CRYPTO frames flooding in quiche
- CVE-2025-4820 Incorrect congestion window growth by optimistic ACK
Sources
Also known as GHSA-w3vp-jw9m-f9pm.