What’s Vulnerable › Vulnerabilities

CVE-2026-118673: KeePassXC: Out-of-bounds write in browser integration response encryption with oversized database responses

• Severity: medium (CVSS 4.1 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-29 · updated 2026-10-29
• Weakness: CWE-787

Description

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.

Affected products

• keepassxreboot keepassxc: from 2.3.0, < 2.8.0

References

• https://github.com/keepassxreboot/keepassxc/commit/80e68bb4e8b89e383dd96b1bf5de169ca61367aa
• https://github.com/keepassxreboot/keepassxc/pull/13679
• https://github.com/keepassxreboot/keepassxc/releases/tag/2.8.0
• https://github.com/keepassxreboot/keepassxc/security/advisories/GHSA-3448-gh8j-3227

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