CVE-2021-46336Public exploit

Process crash via async class-field parsing

Published Jan 20, 2022 · Updated Aug 4, 2024

Reachable assertion in JerryScript 3.0.0 allows local users to crash an embedding process by supplying crafted JavaScript class syntax. In parser_parse_class_body, parsing an async class-field identifier before a constructor leaves the constructor-present option unset, then checks that option with a fatal assertion. Execution requires a process to parse attacker-controlled script text; the demonstrated debug build aborts, interrupting that process without reported data access or modification.

CVSS severity5.5
Medium
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in JerryScript 3.0.0 allows local users to crash an embedding process by supplying crafted JavaScript class syntax. In parser_parse_class_body, parsing an async class-field identifier before a constructor leaves the constructor-present option unset, then checks that option with a fatal assertion. Execution requires a process to parse attacker-controlled script text; the demonstrated debug build aborts, interrupting that process without reported data access or modification.

The record

CVE
CVE-2021-46336
Published
Jan 20, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-617, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 20, 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

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

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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-617Reachable Assertion
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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