CVE-2023-5727Network attack vector

Command execution via unflagged Windows application packages

Published Oct 24, 2023 · Updated Sep 11, 2024

Protection bypass in Firefox before 119, Firefox ESR before 115.4, and Thunderbird before 115.4.1 allows remote attackers to trigger commands. The download-protection extension list did not classify .msix, .msixbundle, .appx, or .appxbundle files as dangerous, suppressing reputation checks and the executable warning before Windows opened the installer. Exploitation requires a Windows user to download and open a crafted package; other operating systems are unaffected, and no command runs without that interaction.

CVSS severity6.5
Medium
EPSS probability0.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Protection bypass in Firefox before 119, Firefox ESR before 115.4, and Thunderbird before 115.4.1 allows remote attackers to trigger commands. The download-protection extension list did not classify .msix, .msixbundle, .appx, or .appxbundle files as dangerous, suppressing reputation checks and the executable warning before Windows opened the installer. Exploitation requires a Windows user to download and open a crafted package; other operating systems are unaffected, and no command runs without that interaction.

The record

CVE
CVE-2023-5727
Published
Oct 24, 2023
Updated
Sep 11, 2024
Vendor
Mozilla
Product
Firefox
Classifications
T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 24, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 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 <119

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <119
Mozilla · Thunderbirdversion=unspecified <115.4.1
Mozilla · Firefox ESRversion=unspecified <115.4

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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.

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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