KeePassXC: Out-of-bounds write in browser integration response encryption with oversized database responses
CVE-2026-118673 is fixed in 2 products on 3 platforms, first by KeePassXC 2.8.0, released October 21, 2026. It is not reported as exploited. Patch Radar priority: Routine.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Windows apps | |||
| KeePassXC | 2.8.0 | KeePassXC 2.8.0 | Oct 21, 2026 |
| macOS | |||
| KeePassXC | 2.8.0 | KeePassXC 2.8.0 | Oct 23, 2026 |
| Linux | |||
| keepassxc · Debian 14 | 2.8.0+dfsg1-1 | DEBIAN-CVE-2026-118673 | Nov 4, 2026 |
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