Mjs
CVE-2023-49552
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, read limits
MITRE ATT&CK
1 technique across 1 tactic: Collection The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available. EPSS exploitation probability: 0.45%. |
| Exploit ScenarioDerived | A remote attacker could read data from memory outside the intended buffer boundaries by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAIv1 – Mar 28, 2026
An Out of Bounds Write in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs_op_json_stringify function in the msj.c file. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
Earlier versions of this analysis (1)
DoS in mjs JS engine.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate array indices and buffer lengths. Use memory-safe languages. Enable AddressSanitizer during testing.
Affects your stack
Find out whether the stacks and servers you run are on an affected version.
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Out-of-bounds Read (CWE-125), which allows attackers to read data from memory outside the intended buffer boundaries. An Out of Bounds Write in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs_op_json_stringify function in the msj.c file. Affected products include: Cesanta Mjs.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
Lifecycle Timeline
2DescriptionCVE.org
An Out of Bounds Write in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs_op_json_stringify function in the msj.c file.
Executive ViewAI
Organizations using An Out of Bounds Write in Cesanta mjs 2.20.0 face notable risk from CVE-2023-49552, a out-of-bounds read vulnerability rated CVSS 7.5. Exploitation could compromise the security of affected deployments. Proof-of-concept code is publicly available, increasing the risk of exploitation. Organizations should apply vendor updates when available and consider compensating controls in the interim.
Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)CVE.org
Cesanta MJS 2.20.0 has a getprop_builtin_foreign out-of-bounds read if a Built-in API name occurs in a substring of an i
Cesanta mjs v2.20.0 was discovered to contain a function pointer hijacking vulnerability via the function mjs_get_ptr().
An issue in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs+0x4ec508 component. Rat
An issue in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs_getretvalpos function i
An issue in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs_op_json_parse function
An issue in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs_destroy function in the
An issue in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs_do_gc function in the m
An issue in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs_array_length function i
An issue found in Cesanta MJS v.1.26 allows a local attacker to cause a denial of service via the mjs_execute function i
Buffer Overflow vulnerability found in Cesanta MJS v.1.26 allows a local attacker to cause a denial of service via the m
Cesanta MJS v2.20.0 was discovered to contain a SEGV vulnerability via mjs_ffi_cb_free at src/mjs_ffi.c. Rated medium se
Cesanta MJS v2.20.0 was discovered to contain a SEGV vulnerability via ffi_cb_impl_wpwwwww at src/mjs_ffi.c. Rated mediu
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