Mozilla Thunderbird up to 141 memory corruption

Summaryinfo

A vulnerability marked as critical has been reported in Mozilla Thunderbird up to 141. Affected by this issue is some unknown functionality. This manipulation causes memory corruption. This vulnerability is registered as CVE-2025-9185. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Mozilla Thunderbird up to 141. It has been declared as critical. Affected by this vulnerability is an unknown code. The manipulation with an unknown input leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Memory safety bugs present in Firefox ESR 115.26, Firefox ESR 128.13, Thunderbird ESR 128.13, Firefox ESR 140.1, Thunderbird ESR 140.1, Firefox 141 and Thunderbird 141. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 142, Firefox ESR < 115.27, Firefox ESR < 128.14, Firefox ESR < 140.2, Thunderbird < 142, Thunderbird < 128.14, and Thunderbird < 140.2.

It is possible to read the advisory at bugzilla.mozilla.org. This vulnerability is known as CVE-2025-9185 since 08/19/2025. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/12/2025).

The vulnerability scanner Nessus provides a plugin with the ID 252327 (Mozilla Firefox ESR < 115.27), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 142 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (252327) and CERT Bund (WID-SEC-2025-1866). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• SUSE Linux
• Oracle Linux
• IGEL OS
• SUSE openSUSE
• RESF Rocky Linux
• Mozilla Firefox
• Mozilla Firefox ESR
• Mozilla Thunderbird

Productinfo

Type

• Mail Client Software

Vendor

• Mozilla

Name

• Thunderbird

Version

• 141

License

• open-source

Website

• Vendor: https://www.mozilla.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

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