CVE-2025-5265Public exploit

Local code execution via unescaped ampersand

Published May 27, 2025 · Updated Apr 13, 2026

Command injection in Mozilla Firefox before 139 allows attackers to execute local code when a user runs copied cURL text on Windows. DevTools Netmonitor's Copy as cURL feature leaves attacker-controlled ampersands in request-header data unescaped, causing cmd.exe to interpret them as command separators. Exploitation requires the user to copy a crafted request and run the generated command; injected commands execute with that user's privileges.

CVSS severity4.8
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in Mozilla Firefox before 139 allows attackers to execute local code when a user runs copied cURL text on Windows. DevTools Netmonitor's Copy as cURL feature leaves attacker-controlled ampersands in request-header data unescaped, causing cmd.exe to interpret them as command separators. Exploitation requires the user to copy a crafted request and run the generated command; injected commands execute with that user's privileges.

The record

CVE
CVE-2025-5265
Published
May 27, 2025
Updated
Apr 13, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-77, T1204.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. May 27, 2025CVE publishedPublication date reported by the CVE source.
  2. Apr 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.8CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1204.004Malicious Copy and Paste

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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