CVE-2021-24857

Name: CVE-2021-24857
Creator: NVD / NIST
Published: 2021-12-13T11:15:09.117+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.84%

Last modified Jun 17, 2026

CVE-2021-24857 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. The ToTop Link WordPress plugin through 1.7.1 passes base64 encoded user input to the unserialize() PHP function, which could lead to PHP Object injection if a plugin installed on the blog has a suitable gadget chain.. EPSS estimates a 1.84% chance of exploitation in the next 30 days.

Description

The ToTop Link WordPress plugin through 1.7.1 passes base64 encoded user input to the unserialize() PHP function, which could lead to PHP Object injection if a plugin installed on the blog has a suitable gadget chain.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.84%

76.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-502

Affected Software

Vendor	Product	Versions
Nocean	Totop Link	<= 1.7.1

References

https://wpscan.com/vulnerability/518204d8-fbf5-4bfa-9db5-835f908f8d8eExploit, Third Party Advisory
https://wpscan.com/vulnerability/518204d8-fbf5-4bfa-9db5-835f908f8d8eExploit, Third Party Advisory

Timeline

Published: Dec 13, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-24857?

How severe is CVE-2021-24857?

CVE-2021-24857 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.84% probability of exploitation in the next 30 days.

How do I fix CVE-2021-24857?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-24857?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST