High severityKnown ExploitedCVE-2021-40438

Apache HTTP Server-Side Request Forgery (SSRF)

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.

Published Dec 1, 2021Updated Dec 15, 2021Source checked Jul 18, 2026

Upstream Advisory

Key facts

Risk: High
Exploitation: Known exploited
Affected software: Not mapped
Fix availability: Not reported

Recommended action

Review the upstream advisory, identify the affected product in your inventory, and apply the vendor update when one is available.

What this means

Apache HTTP Server-Side Request Forgery (SSRF) is listed in the HOL Guard supply-chain feed, but affected software is not mapped to a package. Review the upstream advisory for the affected product and vendor guidance. This vulnerability is known to be exploited in the wild. 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.

Affected software

Affected software not mapped. Review the upstream record for vendor-specific product and version guidance.

Evidence and references

No references were reported by the source.

Source metadata

Published: Dec 1, 2021
Modified: Dec 15, 2021
Source checked: Jul 18, 2026

Reported by CISA KEV (kev).

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