Mozilla Thunderbird up to 140 on ARM64 WASM br_table memory corruption

Summaryinfo

A vulnerability was found in Mozilla Thunderbird up to 140 on ARM64. It has been classified as critical. The impacted element is the function br_table of the component WASM. The manipulation leads to memory corruption. This vulnerability is uniquely identified as CVE-2025-8028. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Mozilla Thunderbird up to 140 on ARM64. It has been rated as critical. This issue affects the function br_table of the component WASM. The manipulation with an unknown input leads to a memory corruption vulnerability. Using CWE to declare the problem leads to 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. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

On arm64, a WASM `br_table` instruction with a lot of entries could lead to the label being too far from the instruction causing truncation and incorrect computation of the branch address. This vulnerability affects Firefox < 141, Firefox ESR < 115.26, Firefox ESR < 128.13, Firefox ESR < 140.1, Thunderbird < 141, Thunderbird < 128.13, and Thunderbird < 140.1.

The advisory is shared at bugzilla.mozilla.org. The identification of this vulnerability is CVE-2025-8028 since 07/22/2025. The exploitation is known to be difficult. 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. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/08/2025).

The vulnerability scanner Nessus provides a plugin with the ID 242581 (Mozilla Thunderbird < 128.13), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 141 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (242581) and CERT Bund (WID-SEC-2025-1623). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

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

Productinfo

Type

• Mail Client Software

Vendor

• Mozilla

Name

• Thunderbird

Version

• 140

License

• open-source

Website

• Vendor: https://www.mozilla.org/

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion