How severe is CVE-2021-24857?

CVE-2021-24857 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-24857 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-24857?

CVE-2021-24857 affects Nocean Totop Link. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-24857?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-24857 published?

CVE-2021-24857 was published on 2021-12-13 and last updated on 2026-06-17.

CVE-2021-24857

CVE-2021-24857 is a critical-severity vulnerability in Nocean Totop Link with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Nocean Totop Link
Published: 2021-12-13
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-24857?: 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.
How severe is CVE-2021-24857?: CVE-2021-24857 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-24857 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-24857?: CVE-2021-24857 affects Nocean Totop Link. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-24857?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-24857 published?: CVE-2021-24857 was published on 2021-12-13 and last updated on 2026-06-17.

References

https://wpscan.com/vulnerability/518204d8-fbf5-4bfa-9db5-835f908f8d8e

Affected products (1)

cpe:2.3:a:nocean:totop_link:*:*:*:*:*:wordpress:*:*

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