CVE-2026-118673

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

MEDIUM
4.1
CVSS Score
Published: October 29, 2026 at 04:01 PM UTC
Updated: October 29, 2026 at 04:29 PM UTC
1 product affected across 1 vendorKeepassxc

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Severity
MEDIUM4.1
Exploit prediction
EPSS 0.1%

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

2.3.0 ≤ v < 2.8.02.3.0

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

4.1MEDIUMGitHub_M
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-787

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