How severe is CVE-2021-33420?

CVE-2021-33420 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-2021-33420 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-33420?

CVE-2021-33420 affects Replicator Project Replicator. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-33420?

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-2021-33420 published?

CVE-2021-33420 was published on 2022-12-15 and last updated on 2026-06-17.

CVE-2021-33420

CVE-2021-33420 is a critical-severity vulnerability in Replicator Project Replicator 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)
EPSS exploit prediction: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Replicator Project Replicator
Published: 2022-12-15
Last modified: 2026-06-17

Description

A deserialization issue discovered in inikulin replicator before 1.0.4 allows remote attackers to run arbitrary code via the fromSerializable function in TypedArray object.

Frequently asked questions

What is CVE-2021-33420?: A deserialization issue discovered in inikulin replicator before 1.0.4 allows remote attackers to run arbitrary code via the fromSerializable function in TypedArray object.
How severe is CVE-2021-33420?: CVE-2021-33420 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-2021-33420 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-33420?: CVE-2021-33420 affects Replicator Project Replicator. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-33420?: 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-2021-33420 published?: CVE-2021-33420 was published on 2022-12-15 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:replicator_project:replicator:*:*:*:*:*:*:*:*

Other CWE-502 (Deserialization of Untrusted Data) vulnerabilities

CVE-2026-41104 — Critical (CVSS 10.0): Deserialization of untrusted data in Microsoft Planetary Computer Pro allows an unauthorized attacker to disclose…
CVE-2026-43633 — Critical (CVSS 10.0): HestiaCP versions 1.9.0 through 1.9.4 contain a deserialization vulnerability in the web terminal component caused by a…
CVE-2026-33819 — Critical (CVSS 10.0): Deserialization of untrusted data in Microsoft Bing allows an unauthorized attacker to execute code over a network.
CVE-2026-20131 — Critical (CVSS 10.0): A vulnerability in the web-based management interface of Cisco Secure Firewall Management Center (FMC) Software could…
CVE-2026-25632 — Critical (CVSS 10.0): EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water…
CVE-2025-14931 — Critical (CVSS 10.0): Hugging Face smolagents Remote Python Executor Deserialization of Untrusted Data Remote Code Execution Vulnerability.…

Browse all CWE-502 (Deserialization of Untrusted Data) vulnerabilities →