CVE-2023-28427Network attack vector

Denial of service via event-key prototype pollution

Published Mar 28, 2023 · Updated Feb 18, 2025

Prototype pollution in The Matrix.org Foundation matrix-js-sdk before 24.0.0 allows remote attackers to disrupt event processing. In certain configurations, event handling accepts special strings in key positions as object attributes and thereby modifies Object.prototype. A remote server must supply a crafted event; demonstrated effects include denial of service and corrupted or excluded runtime data.

CVSS severity8.2
High
EPSS probability1.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Prototype pollution in The Matrix.org Foundation matrix-js-sdk before 24.0.0 allows remote attackers to disrupt event processing. In certain configurations, event handling accepts special strings in key positions as object attributes and thereby modifies Object.prototype. A remote server must supply a crafted event; demonstrated effects include denial of service and corrupted or excluded runtime data.

The record

CVE
CVE-2023-28427
Published
Mar 28, 2023
Updated
Feb 18, 2025
Vendor
The Matrix.org Foundation
Product
matrix-js-sdk
Classifications
CWE-1321, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 18, 2025Record 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=< 24.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Matrix.org Foundation · matrix-js-sdkversion=< 24.0.0

Published CVSS scores

8.2GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
T1499.004Application or System Exploitation

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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