What’s Vulnerable › Vulnerabilities

CVE-2025-64702: quic-go HTTP/3 QPACK Header Expansion DoS

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-11 · updated 2026-10-14
• Weakness: CWE-770

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.

Affected products

• quic-go: before 0.57.0 — fixed in 0.57.0

How to fix

Upgrade to a fixed version: quic-go 0.57.0. Check the vendor advisory for mitigations.

References

• https://github.com/quic-go/quic-go/commit/5b2d2129f8315da41e01eff0a847ab38a34e83a8
• https://github.com/quic-go/quic-go/security/advisories/GHSA-g754-hx8w-x2g6

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