Integer underflow in OpenVPN on Windows and Android
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- Low · None · High
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
OpenVPN versions 2.7_alpha3 through 2.7.7 on Windows and Android are affected. An integer underflow (CWE-191) occurs when OpenVPN processes crafted domain search options. A remote authenticated server can exploit this to cause a denial of service or disclose memory.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Description from the CNA
An integer underflow in OpenVPN version 2.7_alpha3 through 2.7.7 on Windows and Android allows remote authenticated servers to cause a denial of service or memory disclosure via crafted domain search options
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
The sources list no fixed version for OpenVPN.
Written with Claude Haiku 5.5 from the sources below · 2026-10-28
Vendor assessments
Timeline
- 2026-10-14 Threatist record created from CVE-2026-88964
- 2026-10-14 Alias added: GHSA-wm7f-2ghj-7r8c
- 2026-10-14 Priority changed: MEDIUM → LOW
- 2026-10-15 CISA SSVC decision points changed
- 2026-10-16 Affected versions changed · Red Hat
- 2026-10-16 CVSS score added · Red Hat
References
More OpenVPN vulnerabilities
- TI-2024-01215 Integer overflow in OpenVPN tap-windows6 CVSS 3.1CRITICAL 9.8
- TI-2014-04453 Unquoted Windows search path vulnerability in the ptservice service prior to… CVSS 3.1MEDIUM 5.3
- TI-2022-00467 Authentication bypass in OpenVPN CVSS 3.1CRITICAL 9.8
- TI-2024-18509 Unrestricted file upload in OpenVPN 2 CVSS 3.1CRITICAL 9.8
- TI-2024-16468 The interactive service in OpenVPN 2.6.9 and earlier allows the OpenVPN service pipe to… CVSS 3.1HIGH 7.5
- TI-2023-25309 Use after free in OpenVPN 2 CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-88964 · CVE Program
- CVE-2026-88964 · NVD
- FIRST EPSS
- GHSA-wm7f-2ghj-7r8c · GitHub Advisory Database · CC BY 4.0
- CVE-2026-88964 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences