CVE-2023-49553Public exploitNetwork attack vector

Service crash via malformed script cleanup

Published Jan 2, 2024 · Updated Jun 3, 2025

Denial of service in Cesanta mJS 2.20.0 allows remote attackers to crash an embedding process via a crafted JavaScript file. During error cleanup, mjs_destroy passes the json_visited_stack buffer to mbuf_free, where the published proof of concept reaches a segmentation fault. No authentication or user interaction is required, and the demonstrated consequence is process termination.

CVSS severity7.5
High
EPSS probability0.86%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Cesanta mJS 2.20.0 allows remote attackers to crash an embedding process via a crafted JavaScript file. During error cleanup, mjs_destroy passes the json_visited_stack buffer to mbuf_free, where the published proof of concept reaches a segmentation fault. No authentication or user interaction is required, and the demonstrated consequence is process termination.

The record

CVE
CVE-2023-49553
Published
Jan 2, 2024
Updated
Jun 3, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 2, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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