CVE-2021-31875 — CRITICAL (9.8)

Vulnerability Description

In mjs_json.c in Cesanta MongooseOS mJS 1.26, a maliciously formed JSON string can trigger an off-by-one heap-based buffer overflow in mjs_json_parse, which can potentially lead to redirection of control flow. NOTE: the original reporter disputes the significance of this finding because "there isn’t very much of an opportunity to exploit this reliably for an information leak, so there isn’t any real security impact."

CVSS Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Affected Products

Vendor	Product	Versions
Cesanta	Mongooseos Mjs	1.26

Related Weaknesses (CWE)

CWE-193 CWE-787

References

https://github.com/418sec/mjs/pull/2PatchThird Party Advisory
https://github.com/cesanta/mjs/releases/tag/1.26Release NotesThird Party Advisory
https://huntr.dev/bounties/1-other-mjs/ExploitThird Party Advisory
https://github.com/418sec/mjs/pull/2PatchThird Party Advisory
https://github.com/cesanta/mjs/releases/tag/1.26Release NotesThird Party Advisory
https://huntr.dev/bounties/1-other-mjs/ExploitThird Party Advisory

FAQ

What is CVE-2021-31875?

CVE-2021-31875 is a vulnerability with a CVSS score of 9.8 (CRITICAL). In mjs_json.c in Cesanta MongooseOS mJS 1.26, a maliciously formed JSON string can trigger an off-by-one heap-based buffer overflow in mjs_json_parse, which can potentially lead to redirection of cont...

How severe is CVE-2021-31875?

CVE-2021-31875 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2021-31875?

Check the references section above for vendor advisories and patch information. Affected products include: Cesanta Mongooseos Mjs.