CVE-2021-40822
Published: April 11, 2026
Official Description
GeoServer through 2.18.5 and 2.19.x through 2.19.2 allows SSRF via the option for setting a proxy host.
Risk Analysis
GeoServer is vulnerable to Server-Side Request Forgery (SSRF) through an option for setting a proxy host. This flaw could allow an attacker to make the server issue requests to arbitrary domains, potentially accessing internal resources. Its inclusion in CISA's KEV catalog confirms active exploitation, making it a critical vulnerability.
This vulnerability is actively being exploited in the wild. The flaw is remotely exploitable, as it involves manipulating a proxy host setting.
Update GeoServer to a version beyond 2.18.5 or 2.19.2. Implement strict input validation and whitelist allowed domains for server-side requests.
Technical Analysis
CVE-2021-40822 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2021-40822 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Exploit & PoC Resources
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-40822 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1