CVE-2023-49551Public exploitNetwork attack vector

Engine crash via malformed JSON pointer dereference

Published Jan 2, 2024 · Updated Sep 6, 2024

Improper input validation in Cesanta mjs 2.20.0 allows remote attackers to crash the engine by parsing crafted JSON input. The mjs_op_json_parse function in mjs.c processes malformed JSON into an invalid high-address pointer and dereferences it during a read, producing a segmentation fault. The input must reach JSON.parse through an embedding application's network-facing path; successful exploitation aborts the hosting process only.

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

Improper input validation in Cesanta mjs 2.20.0 allows remote attackers to crash the engine by parsing crafted JSON input. The mjs_op_json_parse function in mjs.c processes malformed JSON into an invalid high-address pointer and dereferences it during a read, producing a segmentation fault. The input must reach JSON.parse through an embedding application's network-facing path; successful exploitation aborts the hosting process only.

The record

CVE
CVE-2023-49551
Published
Jan 2, 2024
Updated
Sep 6, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-20, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 2, 2024CVE publishedPublication date reported by the CVE source.
  2. Sep 6, 2024Record 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

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

CWE-20Improper Input Validation
T1499Endpoint Denial of Service

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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