What is CVE-2023-29569?

CVE-2023-29569 is a medium-severity vulnerability in Cesanta Mjs, classified under NULL Pointer Dereference. CVSS score: 5.5/10. Published 2023-04-14.

How severe is CVE-2023-29569?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Is CVE-2023-29569 known to be exploited?

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

NULL pointer dereference in Cesanta Mjs

CVE-2023-29569

Cesanta MJS v2.20.0 was discovered to contain a SEGV vulnerability via ffi_cb_impl_wpwwwww at src/mjs_ffi.c. This vulnerability can lead to a Denial of Service (DoS).

Published 2023-04-14 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.003 (18.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 18th percentile — 18.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Cesanta Mjs — versions 2.20.0

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

Public proof-of-concept exploits

z1r00/fuzz_

References

github.com/z1r00/fuzz_vuln/blob/main/mjs/SEGV/mjs_ffi/readme.md (Exploit)
github.com/cesanta/mjs/issues/239 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2023-29569?: CVE-2023-29569 is a medium-severity vulnerability in Cesanta Mjs, classified under NULL Pointer Dereference. CVSS score: 5.5/10. Published 2023-04-14.
How severe is CVE-2023-29569?: Medium severity. CVSS v3 base score is 5.5 out of 10.
Is CVE-2023-29569 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.