CVE-2023-25734Public exploitNetwork attack vector

NTLM credential exposure via remote shortcut path

Published Jun 2, 2023 · Updated Jan 9, 2025

Improper .url handling in Firefox before 110 and Firefox ESR or Thunderbird before 102.8 allows remote attackers to leak NTLM credentials. The Windows download path permits a crafted Internet Shortcut to retain a remote IconFile path, causing the operating system to fetch that resource and send an NTLM authentication exchange. A victim must receive the crafted .url file through the affected application on Windows; other operating systems are unaffected, and the bounded impact is disclosure of NTLM authentication material to the remote resource.

CVSS severity8.1
High
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper .url handling in Firefox before 110 and Firefox ESR or Thunderbird before 102.8 allows remote attackers to leak NTLM credentials. The Windows download path permits a crafted Internet Shortcut to retain a remote IconFile path, causing the operating system to fetch that resource and send an NTLM authentication exchange. A victim must receive the crafted .url file through the affected application on Windows; other operating systems are unaffected, and the bounded impact is disclosure of NTLM authentication material to the remote resource.

The record

CVE
CVE-2023-25734
Published
Jun 2, 2023
Updated
Jan 9, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-601, T1187, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 9, 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
Mozilla · Thunderbirdversion=unspecified <102.8
Mozilla · Firefox ESRversion=unspecified <102.8

Published CVSS scores

8.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
8.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A: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 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-601URL Redirection to Untrusted Site ('Open Redirect')
T1187Forced Authentication
T1204.002Malicious File

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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