What is CVE-2020-23303?

CVE-2020-23303 is a critical-severity vulnerability in Jerryscript, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2021-06-10.

How severe is CVE-2020-23303?

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

Is CVE-2020-23303 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in Jerryscript

CVE-2020-23303

There is a heap-buffer-overflow at jmem-poolman.c:165 in jmem_pools_collect_empty in JerryScript 2.2.0.

Vulnerability class: Buffer Overflow

Published 2021-06-10 · 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 (69.7th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 70th percentile — 69.7% 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 — versions 2.2.0

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

Public proof-of-concept exploits

n0-traces/cve_

References

github.com/jerryscript-project/jerryscript/issues/3749 (Exploit, Patch, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2020-23303?: CVE-2020-23303 is a critical-severity vulnerability in Jerryscript, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2021-06-10.
How severe is CVE-2020-23303?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2020-23303 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.