CVE-2021-40438
Apache HTTP Server-Side Request Forgery (SSRF)
Apache · Apache
Vulnerability details
A crafted request uri-path can cause mod_proxy to forward the request to an origin server choosen by the remote user. This issue affects Apache HTTP Server 2.4.48 and earlier.
Added to CISA KEV: 2021-12-01
Ransomware campaign use: Known
CISA due date: 2021-12-15
Defensive guidance from CISA
Apply updates per vendor instructions.
This is the source's required-action field, not an independently validated patch procedure. Refer to the vendor for exact affected versions and fixes.
Source catalog date: 2026-11-06T19:44:45.1797Z · Last retrieved: 2026-11-06 21:02:26 UTC