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Mjs CVE-2023-50044

CRITICAL
Classic Buffer Overflow (CWE-120)
2023-12-20 cve@mitre.org
9.8
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Buffer copy size validation
MITRE ATT&CK

1 technique across 1 tactic: Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available.

Exploit ScenarioDerived

A remote attacker could overflow a buffer to corrupt adjacent memory by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

Act Now Prioritize within 24-48h. Why: CRITICAL severity + public POC available.
Patch available 0.9% exploitation probability (EPSS)

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AnalysisAI

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 input string. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Always validate buffer sizes before copy operations. Use bounded functions (strncpy, snprintf). Enable compiler protections.

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 Buffer Copy without Size Check (CWE-120), which allows attackers to overflow a buffer to corrupt adjacent memory. 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 input string. 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

NVD PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionNVD

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 input string.

Threat Intelligence Overview

EPSS Score
0.9%
Top 46% exploitable
Exploit
POC
Public exploit code exists
Data Quality
3 sources
Confidence: Low

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.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC Yes
EPSS 0.9%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity + public POC available
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

70
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +49
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

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.

Affected Products (CPE)NVD

cpe:2.3:a:cesanta:mjs:2.22.0:*:*:*:*:*:*:*

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Cesanta mjs v2.20.0 was discovered to contain a function pointer hijacking vulnerability via the function mjs_get_ptr().

CVE-2023-49550 HIGH POC
7.5 Jan 02

An issue in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs+0x4ec508 component. Rat

CVE-2023-49549 HIGH POC
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An issue in Cesanta mjs 2.20.0 allows a remote attacker to cause a denial of service via the mjs_getretvalpos function i

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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_s

CVE-2023-49551 HIGH POC
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CVE-2023-49553 HIGH POC
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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

CVE-2024-35386 HIGH POC
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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

CVE-2024-35384 MEDIUM POC
5.5 May 21

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

CVE-2023-30088 MEDIUM POC
5.5 May 09

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

CVE-2023-30087 MEDIUM POC
5.5 May 09

Buffer Overflow vulnerability found in Cesanta MJS v.1.26 allows a local attacker to cause a denial of service via the m

CVE-2023-29570 MEDIUM POC
5.5 Apr 24

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

CVE-2023-29569 MEDIUM POC
5.5 Apr 14

Cesanta MJS v2.20.0 was discovered to contain a SEGV vulnerability via ffi_cb_impl_wpwwwww at src/mjs_ffi.c. Rated mediu

References

Advisories & patches

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