Mozilla Thunderbird up to 128.9.1/137.0.1 on Windows File Name information disclosure

Summaryinfo

A vulnerability was found in Mozilla Thunderbird up to 128.9.1/137.0.1 on Windows. It has been rated as problematic. Affected by this issue is some unknown functionality of the component File Name Handler. The manipulation leads to information disclosure. This vulnerability is referenced as CVE-2025-2830. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Mozilla Thunderbird up to 128.9.1/137.0.1 on Windows and classified as problematic. This issue affects an unknown function of the component File Name Handler. The manipulation with an unknown input leads to a information disclosure vulnerability. Using CWE to declare the problem leads to CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Impacted is confidentiality. The summary by CVE is:

By crafting a malformed file name for an attachment in a multipart message, an attacker can trick Thunderbird into including a directory listing of /tmp when the message is forwarded or edited as a new message. This vulnerability could allow attackers to disclose sensitive information from the victim's system. This vulnerability is not limited to Linux; similar behavior has been observed on Windows as well. This vulnerability was fixed in Thunderbird 137.0.2 and Thunderbird 128.9.2.

The advisory is shared at bugzilla.mozilla.org. The identification of this vulnerability is CVE-2025-2830 since 03/26/2025. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 04/15/2026). MITRE ATT&CK project uses the attack technique T1592 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 234457 (Mozilla Thunderbird < 128.9.2), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 128.9.2 or 137.0.2 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (234457). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Mail Client Software

Vendor

• Mozilla

Name

• Thunderbird

Version

• 128.9.0
• 128.9.1
• 137.0.0
• 137.0.1

License

• open-source

Website

• Vendor: https://www.mozilla.org/

CPE 2.3info

• 🔍
• 🔍
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CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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