CVE-2023-25731Public exploitNetwork attack vector

DevTools panel crash via URL prototype pollution

Published Jun 2, 2023 · Updated Jan 10, 2025

Prototype pollution in Firefox before 110 allows remote attackers to disrupt DevTools by supplying a URL with a crafted query parameter. URLPreview.parseUrl reduces query fields into a normal object, so a proto field resolves through the object's prototype chain instead of a dictionary entry. The target must open Developer Tools, select Network, load the crafted page, and inspect its request; the demonstrated consequence is a Netmonitor panel crash.

CVSS severity8.8
High
EPSS probability0.56%
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 Firefox before 110 allows remote attackers to disrupt DevTools by supplying a URL with a crafted query parameter. URLPreview.parseUrl reduces query fields into a normal object, so a proto field resolves through the object's prototype chain instead of a dictionary entry. The target must open Developer Tools, select Network, load the crafted page, and inspect its request; the demonstrated consequence is a Netmonitor panel crash.

The record

CVE
CVE-2023-25731
Published
Jun 2, 2023
Updated
Jan 10, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-1284
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 10, 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=unspecified <110

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <110

Published CVSS scores

8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/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

CWE-1284Improper Validation of Specified Quantity in Input

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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