CVE-2025-11955Network attack vector

Tunnel establishment via fail-open OCSP validation

Published Oct 27, 2025 · Updated Oct 27, 2025

Improper certificate revocation checking in TheGreenBow Windows Enterprise VPN Client 7.5 and 7.6 allows remote attackers to cause IKEv2 tunnel establishment. The client treats a missing OCSP response or one with an invalid signature as sufficient and completes gateway authentication instead of rejecting it. Exploitation requires the OCSP option to be enabled; the resulting trust failure compromises the confidentiality of protected communications.

CVSS severity8.2
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate revocation checking in TheGreenBow Windows Enterprise VPN Client 7.5 and 7.6 allows remote attackers to cause IKEv2 tunnel establishment. The client treats a missing OCSP response or one with an invalid signature as sufficient and completes gateway authentication instead of rejecting it. Exploitation requires the OCSP option to be enabled; the resulting trust failure compromises the confidentiality of protected communications.

The record

CVE
CVE-2025-11955
Published
Oct 27, 2025
Updated
Oct 27, 2025
Vendor
TheGreenBow
Product
TheGreenBow Windows Enterprise VPN Client
Classifications
CWE-299, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 27, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 27, 2025Record 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=7.5
  2. Affected versionversion=7.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

TheGreenBow · TheGreenBow Windows Enterprise VPN Clientversion=7.5; version=7.6

Published CVSS scores

8.2INCIBECVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-299Improper Check for Certificate Revocation
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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