CVE-2025-64702 quic-go HTTP/3 QPACK Header Expansion DoS
Attackers can cause memory exhaustion and denial of service in quic-go applications by sending crafted QPACK-encoded HTTP/3 headers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-64702?
CVE-2025-64702 is a medium-severity denial of service vulnerability in quic-go, published on 11 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
quic-go is an implementation of the QUIC protocol in Go. Versions 0.56.0 and below are vulnerable to excessive memory allocation through quic-go's HTTP/3 client and server implementations by sending a QPACK-encoded HEADERS frame that decodes into a large header field section (many unique header names and/or large values). The implementation builds an http.Header (used on the http.Request and http.Response, respectively), while only enforcing limits on the size of the (QPACK-compressed) HEADERS frame, but not on the decoded header, leading to memory exhaustion. This issue is fixed in version 0.57.0.
Weakness: CWE-770
Which versions are affected by CVE-2025-64702?
3 open source packages ship an affected version, including github.com/quic-go/quic-go. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/quic-go/quic-go Go | All versions | 0.57.0 |
github.com/quic-go/quic-go Go | All versions | 0.57.0 |
github.com/quic-go/quic-go Go | All versions | 0.57.0 |
Linux distribution packages (1)
teleport openSUSE:Tumbleweed | All versions | 17.7.13-1.1 |
Products include Quic-Go Project Quic-Go.
How do I fix CVE-2025-64702?
Upgrade github.com/quic-go/quic-go to 0.57.0 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-2025-64702 being exploited?
There is no known exploitation of CVE-2025-64702 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Other vulnerabilities in quic-go
Sources
Also known as CLEANSTART-2026-DX97509, CLEANSTART-2026-EJ15157, CLEANSTART-2026-QC97945, DEBIAN-CVE-2025-64702, GHSA-g754-hx8w-x2g6, GO-2025-4233 and 22 more.