CVE-2023-43338Public exploitNetwork attack vector

Arbitrary code execution via unchecked function pointer

Published Sep 22, 2023 · Updated Sep 24, 2024

Function pointer hijacking in Cesanta mjs 2.20.0 allows remote attackers to execute arbitrary code through crafted JavaScript input. In mjs_execute, a value returned by mjs_get_ptr is cast to a C function pointer and invoked without validating the resulting call target. No authentication or user interaction is required; the published proof of concept reaches the unchecked call and terminates with an illegal instruction.

CVSS severity9.8
Critical
EPSS probability0.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Function pointer hijacking in Cesanta mjs 2.20.0 allows remote attackers to execute arbitrary code through crafted JavaScript input. In mjs_execute, a value returned by mjs_get_ptr is cast to a C function pointer and invoked without validating the resulting call target. No authentication or user interaction is required; the published proof of concept reaches the unchecked call and terminates with an illegal instruction.

The record

CVE
CVE-2023-43338
Published
Sep 22, 2023
Updated
Sep 24, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 22, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 24, 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

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.

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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

CWE-787Out-of-bounds Write

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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