Buffer overflow in Cesanta Mongooseos Mjs

CVE-2021-31875

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."

EPSS: 0.022 (80.4th percentile) — read the EPSS interpretation.

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.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2021-31875?
CVE-2021-31875 is a critical-severity vulnerability in Cesanta Mongooseos Mjs, classified under Off-by-one Error. CVSS score: 9.8/10. Published 2021-04-29.
How severe is CVE-2021-31875?
Critical severity. CVSS v3 base score is 9.8 out of 10.