CVE-2023-49549Public exploitNetwork attack vector

Interpreter crash via invalid call-stack return position

Published Jan 2, 2024 · Updated Jun 16, 2025

Denial of service in Cesanta mjs 2.20.0 allows remote attackers to crash the interpreter by executing a crafted JavaScript file. The crafted program reaches mjs_getretvalpos with an empty or nonnumeric call-stack return-position entry, and the function asserts instead of handling that state. Execution of the crafted script is required; the failed assertion aborts the mjs process without establishing data disclosure or code execution.

CVSS severity7.5
High
EPSS probability0.76%
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 the interpreter by executing a crafted JavaScript file. The crafted program reaches mjs_getretvalpos with an empty or nonnumeric call-stack return-position entry, and the function asserts instead of handling that state. Execution of the crafted script is required; the failed assertion aborts the mjs process without establishing data disclosure or code execution.

The record

CVE
CVE-2023-49549
Published
Jan 2, 2024
Updated
Jun 16, 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 16, 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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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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