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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (2.17%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 2.17% probability · 81th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-193, CWE-787
- Affected
- cesanta/mongooseos mjs
- Source
- cve@mitre.org
References
- https://github.com/418sec/mjs/pull/2Patch, Third Party Advisory
- https://github.com/cesanta/mjs/releases/tag/1.26Release Notes, Third Party Advisory
- https://huntr.dev/bounties/1-other-mjs/Exploit, Third Party Advisory
- https://github.com/418sec/mjs/pull/2Patch, Third Party Advisory
- https://github.com/cesanta/mjs/releases/tag/1.26Release Notes, Third Party Advisory
- https://huntr.dev/bounties/1-other-mjs/Exploit, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.