CVE-2019-17019Network attack vector

Code execution via misleading Python download handler

Published Jan 8, 2020 · Updated Aug 5, 2024

File-handling error in Mozilla Firefox before 72 allows remote attackers to execute Python code through a crafted text/plain download. The download dialog identifies a .py attachment as text for Notepad, but Firefox passes the file to ShellExecuteW, which selects Python by extension. Exploitation requires Windows with Python installed and user interaction to choose Open; the script then runs with the user's privileges.

CVSS severity8.8
High
EPSS probability1.05%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

File-handling error in Mozilla Firefox before 72 allows remote attackers to execute Python code through a crafted text/plain download. The download dialog identifies a .py attachment as text for Notepad, but Firefox passes the file to ShellExecuteW, which selects Python by extension. Exploitation requires Windows with Python installed and user interaction to choose Open; the script then runs with the user's privileges.

The record

CVE
CVE-2019-17019
Published
Jan 8, 2020
Updated
Aug 5, 2024
Vendor
Mozilla
Product
Firefox
Classifications
T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 8, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=before 72

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=before 72

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1204.002Malicious File

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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