What’s Vulnerable › Vulnerabilities

CVE-2023-6193: Unbounded queuing of path validation messages in cloudflare-quiche

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-12-12 · updated 2026-06-17
• Weakness: CWE-400

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.

Affected products

• Cloudflare quiche: from 0.15.0 through 0.19.0

References

• https://datatracker.ietf.org/doc/html/rfc9000#section-8.2
• https://github.com/cloudflare/quiche/security/advisories/GHSA-w3vp-jw9m-f9pm
• https://datatracker.ietf.org/doc/html/rfc9000#section-8.2
• https://github.com/cloudflare/quiche/security/advisories/GHSA-w3vp-jw9m-f9pm

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