CVE-2020-23315Public exploitNetwork attack vector

Denial of service via yield-register assertion

Published Jan 20, 2022 · Updated Aug 4, 2024

Denial of service in ChakraCore 1.12.0.0-beta allows remote attackers to crash a debug build by supplying crafted JavaScript. During debugger source rundown and reparsing, Js::DebugContext::RundownSourcesAndReparse fails to preserve the function body's yield-register value and violates an equality assertion. The published test requires WScript.Attach and a debug build; the assertion failure terminates the engine with an illegal instruction, limiting the demonstrated impact to a crash.

CVSS severity7.5
High
EPSS probability2.37%
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 ChakraCore 1.12.0.0-beta allows remote attackers to crash a debug build by supplying crafted JavaScript. During debugger source rundown and reparsing, Js::DebugContext::RundownSourcesAndReparse fails to preserve the function body's yield-register value and violates an equality assertion. The published test requires WScript.Attach and a debug build; the assertion failure terminates the engine with an illegal instruction, limiting the demonstrated impact to a crash.

The record

CVE
CVE-2020-23315
Published
Jan 20, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499.004
Attack vector
network
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 vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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.

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 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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