CVE-2021-46512Public exploit

Interpreter crash via non-callable apply receiver

Published Jan 27, 2022 · Updated Aug 4, 2024

Denial of service in Cesanta mJS 2.20.0 allows context-dependent attackers to crash the interpreter via crafted JavaScript. The getprop_builtin path exposes apply on a non-callable numeric receiver, and mjs_apply then performs a null-address read instead of rejecting the receiver. A host application must execute attacker-controlled script; the demonstrated consequence is an interpreter abort, with no reported data access or code execution.

CVSS severity5.5
Medium
EPSS probability0.61%
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 context-dependent attackers to crash the interpreter via crafted JavaScript. The getprop_builtin path exposes apply on a non-callable numeric receiver, and mjs_apply then performs a null-address read instead of rejecting the receiver. A host application must execute attacker-controlled script; the demonstrated consequence is an interpreter abort, with no reported data access or code execution.

The record

CVE
CVE-2021-46512
Published
Jan 27, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 27, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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 vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
4.3NVDAV:N/AC:M/Au:N/C:N/I:N/A:P

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
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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