CVE-2021-33440 json
An issue was discovered in mjs (mJS: Restricted JavaScript engine), ES6 (JavaScript version 6).
published 2022-07-26 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-20144
- cvss
- 5.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 24%
- public exploits
- 0
- none known
Summary
An issue was discovered in mjs (mJS: Restricted JavaScript engine), ES6 (JavaScript version 6). There is NULL pointer dereference in mjs_bcode_commit() in mjs.c.
Patch / fix
Exploit prediction
0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/cesanta/mjs/issues/163 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 5.5 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |
Classification
- Weakness
-
- CWE-476 NULL Pointer Dereference
References
-
github.com
/cesanta/mjs/issues/163
exploit, issue-tracking, patch, third-party-advisory
-
gist.github.com
/Clingto/bb632c0c463f4b2c97e4f65f751c5e6d
third-party-advisory
Sources
- CVE List CVE-2021-33440
- NVD CVE-2021-33440
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.