How severe is CVE-2020-28871?

CVE-2020-28871 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2020-28871?

Affected package information for CVE-2020-28871 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2020-28871?

No fixed version has been published for CVE-2020-28871 yet. Monitor the advisory for updates, apply mitigations recommended by the vendor, and use O3 Security to track when a fix becomes available in your stack.

Is CVE-2020-28871 actively exploited in the wild?

Yes. There are 5 known exploit references for CVE-2020-28871, including 5 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2020-28871?

CVE-2020-28871 has an EPSS (Exploit Prediction Scoring System) score of 93.9%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

Is there exploit tooling available for CVE-2020-28871?

A Nuclei detection template exists for CVE-2020-28871, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2020-28871 published, and has it been updated?

CVE-2020-28871 was published on February 10, 2021 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2020-28871

CRITICAL

Published

Feb 10, 2021

Updated

Apr 10, 2026

Affected

0 pkgs

Patched

None yet

Exploits

5 known

EPSS Exploitation Probability

via FIRST.org ↗

93.9%probability of exploitation in next 30 days

Very High Risk100th percentile0.00%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Description

Remote code execution in Monitorr v1.7.6m in upload.php allows an unauthorized person to execute arbitrary code on the server-side via an insecure file upload.

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.