CVE-2026-86776: KeePass 2.35 through 2.61.1 Memory Exhaustion via KDBX Header Field Size

Severity: low (CVSS 3.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-09 · updated 2026-09-10
Weakness: CWE-789

Description

KeePass versions 2.35 through 2.61.1 fail to validate KDBX header field sizes before memory allocation in the ReadHeaderField function. Attackers can craft a malicious KDBX file declaring excessive header field lengths to trigger allocation of gigabytes of memory, causing the application to consume resources and terminate.

Affected products

KeePass: from 2.35 through 2.61.1

References

https://github.com/KSecur1ty/KDBX-Header-Size-Mirage-POC
https://keepass.info/
https://keepass.info/download.html
https://www.vulncheck.com/advisories/keepass-2.35-through-2.61.1-memory-exhaustion-via-kdbx-header-field-size

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