CVE-2026-53591

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Source

https://cve.org/CVERecord?id=CVE-2026-53591

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53591.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-53591

Aliases

GHSA-8vm3-wwq4-ggfx

Published

2026-07-20T19:47:18.338Z

Modified

2026-07-23T03:56:38.981097836Z

Severity

8.6 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L CVSS Calculator

Summary

FreeScout Vulnerable to Unauthenticated Conversation Thread Injection via HMAC Length Bypass in FetchEmails

Details

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.223, an unauthenticated attacker can inject messages into any existing support conversation by sending a single email to the helpdesk's public address with a crafted In-Reply-To header. No credentials, tokens, or prior access are required. The injected message is rendered in the agent UI as a legitimate customer reply, the conversation is automatically reopened, and the last_reply_from field is set to the attacker's identity. Version 1.8.223 contains a fix.

Database specific

{
    "cna_assigner": "GitHub_M",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53591.json",
    "cwe_ids": [
        "CWE-287"
    ]
}

References

Affected packages

Git / github.com/freescout-help-desk/freescout

Affected ranges

Type

GIT

Repo

https://github.com/freescout-help-desk/freescout

Events

Introduced

Fixed

7cb9f8c713651163065269cef3c3973a4e5bda5f

Database specific

{
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "1.8.223"
        }
    ],
    "source": "AFFECTED_FIELD"
}

Affected versions

1.*

1.0.0

1.0.2

1.0.3

1.0.4

1.0.5

1.0.6

1.0.7

1.0.8

1.0.9

1.1.0

1.1.1

1.1.10

1.1.2

1.1.3

1.1.4

1.1.5

1.1.6

1.1.7

1.1.8

1.1.9

1.2.0

1.2.1

1.2.2

1.2.3

1.2.4

1.2.5

1.2.6

1.3.0

1.3.1

1.3.10

1.3.11

1.3.12

1.3.13

1.3.14

1.3.15

1.3.16

1.3.17

1.3.18

1.3.19

1.3.2

1.3.3

1.3.4

1.3.5

1.3.6

1.3.7

1.3.8

1.3.9

1.4.0

1.4.1

1.4.10

1.4.11

1.4.12

1.4.2

1.4.3

1.4.4

1.4.6

1.4.7

1.4.8

1.4.9

1.5.0

1.5.1

1.5.10

1.5.11

1.5.12

1.5.13

1.5.14

1.5.15

1.5.2

1.5.3

1.5.4

1.5.5

1.5.6

1.5.7

1.5.8

1.5.9

1.6.0

1.6.1

1.6.10

1.6.11

1.6.12

1.6.13

1.6.14

1.6.15

1.6.16

1.6.17

1.6.18

1.6.19

1.6.2

1.6.20

1.6.3

1.6.4

1.6.5

1.6.6

1.6.7

1.6.8

1.6.9

1.7.0

1.7.1

1.7.10

1.7.11

1.7.12

1.7.13

1.7.14

1.7.15

1.7.16

1.7.17

1.7.18

1.7.19

1.7.2

1.7.20

1.7.21

1.7.22

1.7.23

1.7.24

1.7.25

1.7.26

1.7.27

1.7.28

1.7.3

1.7.30

1.7.4

1.7.5

1.7.6

1.7.7

1.7.9

1.8.0

1.8.1

1.8.10

1.8.100

1.8.101

1.8.102

1.8.103

1.8.104

1.8.105

1.8.106

1.8.107

1.8.108

1.8.109

1.8.11

1.8.110

1.8.111

1.8.112

1.8.113

1.8.114

1.8.115

1.8.116

1.8.117

1.8.118

1.8.119

1.8.12

1.8.120

1.8.121

1.8.122

1.8.123

1.8.124

1.8.125

1.8.126

1.8.127

1.8.128

1.8.129

1.8.13

1.8.130

1.8.131

1.8.132

1.8.133

1.8.134

1.8.135

1.8.136

1.8.137

1.8.138

1.8.139

1.8.14

1.8.140

1.8.141

1.8.142

1.8.143

1.8.144

1.8.145

1.8.146

1.8.147

1.8.148

1.8.149

1.8.15

1.8.150

1.8.151

1.8.152

1.8.153

1.8.154

1.8.155

1.8.156

1.8.157

1.8.158

1.8.159

1.8.16

1.8.160

1.8.161

1.8.162

1.8.163

1.8.164

1.8.165

1.8.166

1.8.167

1.8.168

1.8.169

1.8.17

1.8.170

1.8.171

1.8.172

1.8.173

1.8.174

1.8.175

1.8.176

1.8.177

1.8.178

1.8.179

1.8.18

1.8.180

1.8.181

1.8.182

1.8.183

1.8.184

1.8.185

1.8.186

1.8.187

1.8.188

1.8.189

1.8.19

1.8.190

1.8.191

1.8.192

1.8.193

1.8.194

1.8.195

1.8.196

1.8.197

1.8.198

1.8.199

1.8.2

1.8.20

1.8.200

1.8.201

1.8.202

1.8.203

1.8.204

1.8.205

1.8.206

1.8.207

1.8.208

1.8.209

1.8.21

1.8.210

1.8.211

1.8.212

1.8.213

1.8.214

1.8.215

1.8.216

1.8.217

1.8.218

1.8.219

1.8.22

1.8.220

1.8.221

1.8.222

1.8.23

1.8.24

1.8.25

1.8.26

1.8.27

1.8.28

1.8.29

1.8.3

1.8.30

1.8.31

1.8.32

1.8.33

1.8.34

1.8.35

1.8.36

1.8.37

1.8.38

1.8.39

1.8.4

1.8.40

1.8.41

1.8.42

1.8.43

1.8.44

1.8.45

1.8.46

1.8.47

1.8.48

1.8.49

1.8.5

1.8.50

1.8.51

1.8.52

1.8.53

1.8.54

1.8.55

1.8.56

1.8.57

1.8.58

1.8.59

1.8.6

1.8.60

1.8.61

1.8.62

1.8.63

1.8.65

1.8.66

1.8.67

1.8.68

1.8.69

1.8.7

1.8.70

1.8.71

1.8.72

1.8.73

1.8.74

1.8.75

1.8.76

1.8.77

1.8.78

1.8.79

1.8.8

1.8.80

1.8.81

1.8.82

1.8.83

1.8.84

1.8.85

1.8.86

1.8.87

1.8.88

1.8.89

1.8.9

1.8.90

1.8.91

1.8.92

1.8.93

1.8.94

1.8.95

1.8.96

1.8.97

1.8.98

1.8.99

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53591.json"