What is CVE-2021-42863?

CVE-2021-42863 is a critical-severity vulnerability in Jerryscript, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2022-05-12.

How severe is CVE-2021-42863?

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

Buffer overflow in Jerryscript

CVE-2021-42863

A buffer overflow in ecma_builtin_typedarray_prototype_filter() in JerryScript version fe3a5c0 allows an attacker to construct a fake object or a fake arraybuffer with unlimited size.

Vulnerability class: Buffer Overflow

Published 2022-05-12 · 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 (76.3th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 76th percentile — 76.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

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

Affected products

Jerryscript

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

References

github.com/jerryscript-project/jerryscript/issues/4793 (Exploit, Patch, Third Party Advisory)
github.com/jerryscript-project/jerryscript/pull/4794 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-42863?: CVE-2021-42863 is a critical-severity vulnerability in Jerryscript, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2022-05-12.
How severe is CVE-2021-42863?: Critical severity. CVSS v3 base score is 9.8 out of 10.