CVE-2023-5654Public exploitNetwork attack vector

Arbitrary browser fetches via unvalidated window messages

Published Oct 19, 2023 · Updated Sep 12, 2024

Improper authorization in Meta React Developer Tools before 4.28.4 allows remote attackers to issue arbitrary browser fetches. The content script accepts page-controlled fetch-file-with-cache messages from window and passes the supplied URL to fetch without validation. Any active webpage can invoke the listener when the affected extension is installed, enabling unauthorized outbound requests and traffic generation from the browser.

CVSS severity6.9
Medium
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in Meta React Developer Tools before 4.28.4 allows remote attackers to issue arbitrary browser fetches. The content script accepts page-controlled fetch-file-with-cache messages from window and passes the supplied URL to fetch without validation. Any active webpage can invoke the listener when the affected extension is installed, enabling unauthorized outbound requests and traffic generation from the browser.

The record

CVE
CVE-2023-5654
Published
Oct 19, 2023
Updated
Sep 12, 2024
Vendor
Meta
Product
React Developer Tools Extension
Classifications
CWE-285, CWE-116
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 19, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 12, 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=< 4.28.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Meta · React Developer Tools Extensionversion=< 4.28.4

Published CVSS scores

6.5NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
6.9GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-285Improper Authorization
CWE-116Improper Encoding or Escaping of Output

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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