CVE-2021-46463Public exploitNetwork attack vector

Control-flow hijacking via inherited Promise misclassification

Published Feb 14, 2022 · Updated Aug 4, 2024

Type confusion in njs 0.7.1 and earlier allows attackers to corrupt memory and hijack control flow via crafted Promise objects. Promise resolution accepts objects that merely inherit from Promise as genuine Promise instances, then njs_promise_perform_then writes is_handled through an incompatible data pointer. Triggering the flaw requires attacker-crafted JavaScript to execute in an njs VM; a published proof of concept demonstrates process memory corruption and a crash.

CVSS severity9.8
Critical
EPSS probability1.68%
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 njs 0.7.1 and earlier allows attackers to corrupt memory and hijack control flow via crafted Promise objects. Promise resolution accepts objects that merely inherit from Promise as genuine Promise instances, then njs_promise_perform_then writes is_handled through an incompatible data pointer. Triggering the flaw requires attacker-crafted JavaScript to execute in an njs VM; a published proof of concept demonstrates process memory corruption and a crash.

The record

CVE
CVE-2021-46463
Published
Feb 14, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-843
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 14, 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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV: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.

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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-843Access of Resource Using Incompatible Type ('Type Confusion')

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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