CVE intelligence and bounded remediation

CVE-2020-23776 — A SSRF vulnerability exists in Winmail 6.5 in app.php in the key parameter when HTTPS is on

High CVSS 7.5

A SSRF vulnerability exists in Winmail 6.5 in app.php in the key parameter when HTTPS is on. An attacker can use this vulnerability to cause the server to send a request to a specific URL. An attacker can modify the request header 'HOST' value to cause the server to send the request.

Severity
High
CVSS
7.5 (3.1)
Published
2021-01-26
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-918

Affected products

  • winmail_project / winmail / 6.5

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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