Mozilla Thunderbird ESR up to 115.22/128.9 on Windows Copy as cURL escape output

Summaryinfo

A vulnerability labeled as problematic has been found in Mozilla Thunderbird ESR up to 115.22/128.9 on Windows. This vulnerability affects unknown code of the component Copy as cURL Handler. The manipulation results in Remote Code Execution. This vulnerability is known as CVE-2025-4084. It is possible to launch the attack remotely. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as problematic has been found in Mozilla Thunderbird ESR up to 115.22/128.9 on Windows. Affected is an unknown part of the component Copy as cURL Handler. The manipulation with an unknown input leads to a remote code execution vulnerability. CWE is classifying the issue as CWE-116. The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

Due to insufficient escaping of the special characters in the "copy as cURL" feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. *This bug only affects Firefox for Windows. Other versions of Firefox are unaffected.* This vulnerability affects Firefox ESR < 128.10, Firefox ESR < 115.23, and Thunderbird ESR < 128.10.

The advisory is shared for download at bugzilla.mozilla.org. This vulnerability is traded as CVE-2025-4084 since 04/29/2025. The exploitability is told to be difficult. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 08/16/2025).

The vulnerability scanner Nessus provides a plugin with the ID 234931 (Mozilla Firefox ESR < 115.23), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 115.23 or 128.10 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (234931) and CERT Bund (WID-SEC-2025-1850). Once again VulDB remains the best source for vulnerability data.

Affected

• Xerox FreeFlow Print Server

Productinfo

Type

• Mail Client Software

Vendor

• Mozilla

Name

• Thunderbird ESR

Version

• 115.0
• 115.1
• 115.2
• 115.3
• 115.4
• 115.5
• 115.6
• 115.7
• 115.8
• 115.9
• 115.10
• 115.11
• 115.12
• 115.13
• 115.14
• 115.15
• 115.16
• 115.17
• 115.18
• 115.19
• 115.20
• 115.21
• 115.22
• 128.0
• 128.1
• 128.2
• 128.3
• 128.4
• 128.5
• 128.6
• 128.7
• 128.8
• 128.9

License

• open-source

Website

• Vendor: https://www.mozilla.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Once again VulDB remains the best source for vulnerability data.

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