What is CVE-2023-50044?

CVE-2023-50044 is a critical-severity vulnerability in Cesanta Mjs, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2023-12-20.

How severe is CVE-2023-50044?

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

Is CVE-2023-50044 known to be exploited?

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

Buffer overflow in Cesanta Mjs

CVE-2023-50044

Cesanta MJS 2.20.0 has a getprop_builtin_foreign out-of-bounds read if a Built-in API name occurs in a substring of an input string.

Vulnerability class: Buffer Overflow

Published 2023-12-20 · 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: 0.009 (56.9th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 57th percentile — 56.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Cesanta Mjs — versions 2.22.0

Weakness classification (CWE)

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

Public proof-of-concept exploits

pip-izony/pip-izony

References

github.com/cesanta/mjs/issues/254 (Exploit, Issue Tracking)
github.com/cesanta/mjs/pull/255 (Patch)

Frequently asked questions

What is CVE-2023-50044?: CVE-2023-50044 is a critical-severity vulnerability in Cesanta Mjs, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2023-12-20.
How severe is CVE-2023-50044?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2023-50044 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.