CVE intelligence and bounded remediation
CVE-2021-20788 — Groupsession Groupsession security vulnerability
Server-side request forgery (SSRF) vulnerability in GroupSession (GroupSession Free edition from ver2.2.0 to the version prior to ver5.1.0, GroupSession byCloud from ver3.0.3 to the version prior to ver5.1.0, and GroupSession ZION from ver3.0.3 to the version prior to ver5.1.0) allows a remote authenticated attacker to conduct a port scan from the product and/or obtain information from the internal Web server.
- Severity
- Medium
- CVSS
- 4.3 (3.1)
- Published
- 2021-07-30
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-918
Affected products
- groupsession / groupsession
- groupsession / groupsession_bycloud
- groupsession / groupsession_zion
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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