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.
History

Wed, 04 Nov 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 4.4, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Tue, 03 Nov 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 30 Oct 2026 22:45:00 +0000

Type Values Removed Values Added
First Time appeared Keepassxc
Keepassxc keepassxc
Vendors & Products Keepassxc
Keepassxc keepassxc

Thu, 29 Oct 2026 16:15:00 +0000

Type Values Removed Values Added
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.
Title KeePassXC: Out-of-bounds write in browser integration response encryption with oversized database responses
Weaknesses CWE-787
References
Metrics cvssV4_0

{'score': 4.1, 'vector': 'CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-10-29T16:01:55.635Z

Updated: 2026-11-03T16:32:32.671Z

Reserved: 2026-10-28T17:25:37.562Z

Link: CVE-2026-118673

cve-icon Vulnrichment

Updated: 2026-11-03T16:32:17.637Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-29T16:18:03.873

Modified: 2026-11-03T17:17:58.770

Link: CVE-2026-118673

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-29T16:01:55Z

Links: CVE-2026-118673 - Bugzilla