CVE-2023-29542Public exploitNetwork attack vector

Code execution via pre-sanitization extension checks

Published Jun 19, 2023 · Updated Dec 11, 2024

Filename validation in Firefox before 112, Firefox ESR before 102.10, and Thunderbird before 102.10 allows attackers to execute code via downloads. The Windows download path checked dangerous extensions before SanitizeFileName stripped a trailing newline, leaving the sanitized filename unrenamed. A user must accept and open the crafted download; the bypass removes the extension safeguard but does not itself execute the file.

CVSS severity9.8
Critical
EPSS probability0.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Filename validation in Firefox before 112, Firefox ESR before 102.10, and Thunderbird before 102.10 allows attackers to execute code via downloads. The Windows download path checked dangerous extensions before SanitizeFileName stripped a trailing newline, leaving the sanitized filename unrenamed. A user must accept and open the crafted download; the bypass removes the extension safeguard but does not itself execute the file.

The record

CVE
CVE-2023-29542
Published
Jun 19, 2023
Updated
Dec 11, 2024
Vendor
Mozilla
Product
Firefox
Classifications
T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 19, 2023CVE publishedPublication date reported by the CVE source.
  2. Dec 11, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <112

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <112
Mozilla · Thunderbirdversion=unspecified <102.10
Mozilla · Firefox ESRversion=unspecified <102.10

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 exploitPublished

Weakness, pattern, technique

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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