CVE-2020-6797Public exploitNetwork attack vector

Semi-privileged extension launches arbitrary apps via .fileloc

Published Mar 2, 2020 · Updated Aug 4, 2024

Arbitrary application launch in Mozilla Firefox and Thunderbird before their fixed releases allows remote attackers to trigger local app execution via a downloaded .fileloc file on macOS. The downloads.open extension API passes the shortcut file to macOS file handling, which opens the referenced application without permitting command-line arguments or non-quarantined files. Exploitation requires a semi-privileged extension with downloads.open permission and is limited to macOS; other operating systems are unaffected.

CVSS severity4.3
Medium
EPSS probability1.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Arbitrary application launch in Mozilla Firefox and Thunderbird before their fixed releases allows remote attackers to trigger local app execution via a downloaded .fileloc file on macOS. The downloads.open extension API passes the shortcut file to macOS file handling, which opens the referenced application without permitting command-line arguments or non-quarantined files. Exploitation requires a semi-privileged extension with downloads.open permission and is limited to macOS; other operating systems are unaffected.

The record

CVE
CVE-2020-6797
Published
Mar 2, 2020
Updated
Aug 4, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-20, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 2, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=unspecified <73
  2. Affected versionversion=unspecified <ESR68.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <73; version=unspecified <ESR68.5
Mozilla · Thunderbirdversion=unspecified <68.5

Published CVSS scores

4.3NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation
T1203Exploitation for Client Execution

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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