CVE-2023-25729Public exploitNetwork attack vector

Silent external-scheme launch via principal mismatch

Published Jun 2, 2023 · Updated Jan 10, 2025

Incorrect authorization in Mozilla Firefox before 110, Firefox ESR before 102.8, and Thunderbird before 102.8 lets extensions open external schemes. The external-protocol chooser prompts only for ContentPrincipals, so requests attributed to ExpandedPrincipals bypass user confirmation. A malicious installed extension can trigger downloads or pass external-scheme data to installed applications without another user action.

CVSS severity8.8
High
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Mozilla Firefox before 110, Firefox ESR before 102.8, and Thunderbird before 102.8 lets extensions open external schemes. The external-protocol chooser prompts only for ContentPrincipals, so requests attributed to ExpandedPrincipals bypass user confirmation. A malicious installed extension can trigger downloads or pass external-scheme data to installed applications without another user action.

The record

CVE
CVE-2023-25729
Published
Jun 2, 2023
Updated
Jan 10, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-863, T1176
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

Compare your product and version with the public record. A matching version still requires validation against your environment.

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
Mozilla · Thunderbirdversion=unspecified <102.8
Mozilla · Firefox ESRversion=unspecified <102.8

Published CVSS scores

8.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.8NVDCVSS: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-863Incorrect Authorization
T1176Browser Extensions

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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