CVE intelligence and bounded remediation
CVE-2021-40186 — Dnnsoftware Dotnetnuke security vulnerability
The AppCheck research team identified a Server-Side Request Forgery (SSRF) vulnerability within the DNN CMS platform, formerly known as DotNetNuke. SSRF vulnerabilities allow the attacker to exploit the target system to make network requests on their behalf, allowing a range of possible attacks. In the most common scenario, the attacker exploits SSRF vulnerabilities to attack systems behind the firewall and access sensitive information from Cloud Provider metadata services.
- Severity
- High
- CVSS
- 7.5 (3.1)
- Published
- 2022-06-02
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-918
Affected products
- dnnsoftware / dotnetnuke
Matched remediation archetype
Server-side request forgery and unintended proxying
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
Check exposure
- Inventory server-side URL fetchers, webhooks, importers, previews, redirects, proxies, and protocol handlers reachable from untrusted input.
- Map egress paths to internal services, metadata endpoints, loopback, private address space, and privileged control planes.
- Review DNS resolution, redirect, proxy, credential-forwarding, and URL parsing behavior without requesting sensitive targets.
Remediate safely
- Replace arbitrary destinations with named integrations or a strict allowlist of schemes, hosts, ports, and paths.
- Resolve and validate every destination and redirect hop, then enforce egress policy independently of application checks.
- Remove ambient credentials and sensitive headers from fetchers; apply response size, time, and content limits.
Authoritative sources
Complete CVE record and remediation plan
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