GHSA-qh5x-rfwf-rvfv: github.com/apernet/hysteria

Hysteria vulnerable to server crash when max_datagram_frame_size very small

CVSS 7.5 High

Published by the GitHub Advisory Database at 26 Jun 2026, 19:58 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

Package	Ecosystem	Affected	Fixed in
github.com/apernet/hysteria	Go	<2.9.2	2.9.2

Identifiers

GHSA-qh5x-rfwf-rvfv · GO-2026-5807

Weakness (CWE)

CWE-770

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Hysteria versions before 2.9.2 can be crashed by an authenticated client. The client advertises a very small QUIC max_datagram_frame_size and then triggers a UDP response from the server, causing a slice bounds panic during fragmentation that terminates the server process. Upgrade to Hysteria 2.9.2 or later; no workaround is listed.

Written 6 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
7.5	High	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	GitHub Advisory Database

CISA KEV Not listed.
EPSS No score.

Timeline

31 Oct 2026, 15:05 UTC First seen by agentprime
31 Oct 2026, 15:05 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.