CVE-2026-86776Public exploit

Application termination via oversized KDBX header fields

Published Sep 9, 2026 · Updated Sep 10, 2026

Memory exhaustion in KeePass 2.35 through 2.61.1 allows attackers to terminate the application via a crafted KDBX file. ReadHeaderField trusts the four-byte size declared by each KDBX 4 header field and allocates that amount before validating it. A user must open the attacker-supplied database; the allocation can consume gigabytes of memory and terminate KeePass, without reported data exposure or modification.

CVSS severity4.6
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory exhaustion in KeePass 2.35 through 2.61.1 allows attackers to terminate the application via a crafted KDBX file. ReadHeaderField trusts the four-byte size declared by each KDBX 4 header field and allocates that amount before validating it. A user must open the attacker-supplied database; the allocation can consume gigabytes of memory and terminate KeePass, without reported data exposure or modification.

The record

CVE
CVE-2026-86776
Published
Sep 9, 2026
Updated
Sep 10, 2026
Vendor
KeePass
Product
KeePass
Classifications
CWE-789, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 10, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.35 <=2.61.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

KeePass · KeePassversion=2.35 <=2.61.1

Published CVSS scores

4.6VulnCheck CNACVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
3.3VulnCheck CNACVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-789Memory Allocation with Excessive Size Value
T1204.002User Execution: Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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