{"cve":"CVE-2021-31875","nvd":{"published":"2021-04-29T02:15:08.043","modified":"2026-06-17T03:52:23.537","status":"Modified","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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-193","CWE-787"],"references":["https://github.com/418sec/mjs/pull/2","https://github.com/cesanta/mjs/releases/tag/1.26","https://huntr.dev/bounties/1-other-mjs/","https://github.com/418sec/mjs/pull/2","https://github.com/cesanta/mjs/releases/tag/1.26"],"products":["cesanta:mongooseos_mjs"],"source":"nvd","synced_at":"2026-10-19T21:18:09.669877188+00:00"},"epss":{"cve":"CVE-2021-31875","score":0.02174,"percentile":0.82314,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}