Heap overwrite via unterminated JSON copy
Published Apr 29, 2021 · Updated Aug 3, 2024
Heap buffer overflow in Cesanta MongooseOS mJS 1.26 allows attackers to overwrite one heap byte via a maliciously formed JSON string. In mjs_json_parse in mjs_json.c, a copied input buffer lacks space for the terminating null byte, producing a one-byte heap overwrite. Reachability depends on an embedding application passing attacker-controlled JSON to the parser; the finding is disputed because reliable information disclosure or control-flow redirection has not been demonstrated.
Summary
What happened
Heap buffer overflow in Cesanta MongooseOS mJS 1.26 allows attackers to overwrite one heap byte via a maliciously formed JSON string. In mjs_json_parse in mjs_json.c, a copied input buffer lacks space for the terminating null byte, producing a one-byte heap overwrite. Reachability depends on an embedding application passing attacker-controlled JSON to the parser; the finding is disputed because reliable information disclosure or control-flow redirection has not been demonstrated.
The record
- CVE
- CVE-2021-31875
- Published
- Apr 29, 2021
- Updated
- Aug 3, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-787, CWE-193
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 29, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- Malformed JSON heap-overflow proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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