GHSA-jqc5-2p7q-fqfc: github.com/apernet/hysteria

Hysteria: http large header with sniff cause server DoS

CVSS 7.5 High

Published by the GitHub Advisory Database at 26 Jun 2026, 20:19 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-jqc5-2p7q-fqfc · GO-2026-5813

Weakness (CWE)

CWE-770

Machine-written summary

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

Hysteria (Go package github.com/apernet/hysteria) versions before 2.9.2 are vulnerable to a denial of service caused by excessively large HTTP headers during traffic sniffing. A remote attacker who can reach the server can send headers without the end-of-header marker, causing the server to consume large amounts of memory, reportedly up to 16GB in testing, and possibly run out of memory. Upgrade to version 2.9.2 or later.

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.