OpenVPN 2.5.0-2.7.6 Windows OOB Write via DOMAIN-SEARCH (tap-windows6)
CVE-2026-81738 Published on September 7, 2026
OpenVPN 2.5.0 through 2.7.6 on Windows using the tap-windows6 driver allows attackers to trigger an out-of-bounds write via crafted DOMAIN-SEARCH entries
Vulnerability Analysis
CVE-2026-81738 is exploitable with network access. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Types
What is a Stack Overflow Vulnerability?
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
CVE-2026-81738 has been classified to as a Stack Overflow vulnerability or weakness.
What is an off-by-five Vulnerability?
A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.
CVE-2026-81738 has been classified to as an off-by-five vulnerability or weakness.
What is a Memory Corruption Vulnerability?
The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.
CVE-2026-81738 has been classified to as a Memory Corruption vulnerability or weakness.
Products Associated with CVE-2026-81738
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Affected Versions
OpenVPN:- Version 2.5.0, <= 2.7.6 is affected.