CVE-2026-11604Network attack vector

System crash via future-key count overshoot

Published Jun 10, 2026 · Updated Jun 10, 2026

Heap-based buffer overflow in OpenVPN ovpn-dco-win allows remote authenticated users to crash Windows systems via a crafted packet. OvpnCryptoEpochGenerateFutureRecvKeys reads the highest epoch from a consumed future-key slot that has been zeroed, causing numKeysGenerate to overshoot and RtlMoveMemory to write beyond its heap buffer. The packet must come from an authenticated peer using the epoch-key data path; successful exploitation corrupts kernel memory and crashes the host.

CVSS severity5.6
Medium
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in OpenVPN ovpn-dco-win allows remote authenticated users to crash Windows systems via a crafted packet. OvpnCryptoEpochGenerateFutureRecvKeys reads the highest epoch from a consumed future-key slot that has been zeroed, causing numKeysGenerate to overshoot and RtlMoveMemory to write beyond its heap buffer. The packet must come from an authenticated peer using the epoch-key data path; successful exploitation corrupts kernel memory and crashes the host.

The record

CVE
CVE-2026-11604
Published
Jun 10, 2026
Updated
Jun 10, 2026
Vendor
OpenVPN Inc.
Product
OpenVPN Data Channel Offload for Windows
Classifications
CWE-787, CWE-131, CWE-122, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 10, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 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=2.0.0 <=2.5.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OpenVPN Inc. · OpenVPN Data Channel Offload for Windowsversion=2.0.0 <=2.5.8

Published CVSS scores

5.6OpenVPN Inc.CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-131Incorrect Calculation of Buffer Size
CWE-122Heap-based Buffer Overflow
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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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