CVE-2021-24044Network attack vector

Code execution via invalid getter and setter syntax

Published Jan 15, 2022 · Updated Aug 3, 2024

Type confusion in Meta Platforms, Inc. Hermes before 0.10.0 allows attackers to crash the engine or execute code via crafted JavaScript. Hermes invokes generator functions for invalid await or yield expressions in non-async, non-generator getter/setter functions, causing incompatible types to reach error handling. Exploitation requires a host application to evaluate attacker-controlled JavaScript; a successful trigger causes a segmentation fault, with code execution assessed as low probability.

CVSS severity9.8
Critical
EPSS probability1.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in Meta Platforms, Inc. Hermes before 0.10.0 allows attackers to crash the engine or execute code via crafted JavaScript. Hermes invokes generator functions for invalid await or yield expressions in non-async, non-generator getter/setter functions, causing incompatible types to reach error handling. Exploitation requires a host application to evaluate attacker-controlled JavaScript; a successful trigger causes a segmentation fault, with code execution assessed as low probability.

The record

CVE
CVE-2021-24044
Published
Jan 15, 2022
Updated
Aug 3, 2024
Vendor
Meta Platforms, Inc.
Product
Hermes
Classifications
CWE-843, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 15, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <0.10.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Meta Platforms, Inc. · Hermesversion=unspecified <0.10.0

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/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 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 exploitUnconfirmed

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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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