What is CVE-2021-43453?

CVE-2021-43453 is a critical-severity vulnerability in Jerryscript, classified under Out-of-bounds Read. CVSS score: 9.8/10. Published 2022-04-07.

How severe is CVE-2021-43453?

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

Out-of-bounds Read in Jerryscript

CVE-2021-43453

A Heap-based Buffer Overflow vulnerability exists in JerryScript 2.4.0 and prior versions via an out-of-bounds read in parser_parse_for_statement_start in the js-parser-statm.c file. This issue is similar to CVE-2020-29657.

Vulnerability class: Buffer Overflow

Published 2022-04-07 · 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: 0.013 (68.6th percentile), scored 2026-10-07.

Low probability of exploitation in the next 30 days, but still tracked. 69th percentile — 68.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.013 · newest: 0.013 · change: 0.000

Affected products

Jerryscript

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

github.com/jerryscript-project/jerryscript/issues/4754 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2021-43453?: CVE-2021-43453 is a critical-severity vulnerability in Jerryscript, classified under Out-of-bounds Read. CVSS score: 9.8/10. Published 2022-04-07.
How severe is CVE-2021-43453?: Critical severity. CVSS v3 base score is 9.8 out of 10.