CVE-2026-44435 Details
Description
Quicly is an IETF QUIC protocol implementation intended primarily for use within the H2O HTTP server. Prior to commit 937d0e9, an assertion failure is raised when the total number of valid handshake messages received over a CRYPTO stream of a single packet number space exceeds 32KB, causing a Denial of Service. This issue has been fixed by commit 937d0e9.
A denial-of-service vulnerability has been identified in H2O Quicly, an implementation of the IETF QUIC protocol. This issue arises from an assertion failure that occurs when the total number of valid handshake messages received over a CRYPTO stream within a single packet number space exceeds 32KB. The vulnerability is present in versions of Quicly prior to the commit 937d0e9.
Users can update to Quicly version 8b178e6 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 17, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-400 | Uncontrolled Resource Consumption | [email protected] |
| CWE-617 | Reachable Assertion | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| h2o quicly | < 2026-05-29 |
CPE
Remediation
| |
Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Aug 6, 2026 | Initial Analysis | [email protected] |
| Jul 17, 2026 | CVE Modified | CISA-ADP |
| Jul 16, 2026 | New CVE Received | [email protected] |