What is CVE-2021-33420?

CVE-2021-33420 is a critical-severity vulnerability in Replicator Project, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2022-12-15.

How severe is CVE-2021-33420?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Deserialization in Replicator Project

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.

Vulnerability class: Insecure Deserialization

Published 2022-12-15 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.017 (75.8th percentile), scored 2026-10-08.

Low probability of exploitation in the next 30 days, but still tracked. 76th percentile — 75.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.016 · newest: 0.017 · change: +0.000

Affected products

Replicator Project

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

github.com/inikulin/replicator/issues/16 (Third Party Advisory)
github.com/inikulin/replicator/pull/17 (Third Party Advisory)
github.com/inikulin/replicator/commit/2c626242fb4a118855262c64b5731b2ce98e521b (Patch, Third Party Advisory)
advisory.checkmarx.net/advisory/CX-2021-4787 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-33420?: CVE-2021-33420 is a critical-severity vulnerability in Replicator Project, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2022-12-15.
How severe is CVE-2021-33420?: Critical severity. CVSS v3 base score is 9.8 out of 10.