Keepassxreboot KeePassXC up to 2.7.x Browser Integration BrowserMessageBuilder.cpp crypto_box_easy out-of-bounds write

Summaryinfo

A vulnerability categorized as critical has been discovered in Keepassxreboot KeePassXC up to 2.7.x. The affected element is the function Botan::Sodium::crypto_box_easy of the file src/browser/BrowserMessageBuilder.cpp of the component Browser Integration. Executing a manipulation can lead to out-of-bounds write. This vulnerability is tracked as CVE-2026-118673. The attack can be launched remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Keepassxreboot KeePassXC up to 2.7.x. It has been declared as critical. This vulnerability affects the function Botan::Sodium::crypto_box_easy of the file src/browser/BrowserMessageBuilder.cpp of the component Browser Integration. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. The CWE definition for the vulnerability is CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

KeePassXC is a cross-platform community-driven port of the Windows application KeePass Password Safe. From 2.3.0 until 2.8.0, KeePassXC browser integration encrypts authorized responses in src/browser/BrowserMessageBuilder.cpp using a fixed 1 MiB output vector even though Botan::Sodium::crypto_box_easy() writes the plaintext length plus crypto_box_MACBYTES. A browser-protocol client that can access the per-user IPC endpoint, has a valid database association, and causes an unlocked database to generate and encrypt a sufficiently large authorized response can trigger a sequential out-of-bounds write before any response is delivered. This issue is fixed in version 2.8.0.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-118673 since 10/28/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available.

Upgrading to version 2.8.0 eliminates this vulnerability.

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Productinfo

Vendor

• Keepassxreboot

Name

• KeePassXC

Version

• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7

Website

• Product: https://github.com/keepassxreboot/keepassxc/

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