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PatchSiren cyber security CVE debrief

CVE-2026-40215 OpenVPN CVE debrief

CVE-2026-40215 is a medium-severity vulnerability in OpenVPN, allowing remote attackers to potentially cause a server crash or leak heap memory via a use-after-free triggered during TLS session promotion. The vulnerability affects OpenVPN versions 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1.

Vendor
OpenVPN
Product
Unknown
CVSS
MEDIUM 6.1
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-08
Original CVE updated
2026-08-11
Advisory published
2026-06-08
Advisory updated
2026-08-11

Who should care

Users of OpenVPN versions 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1 should be aware of this vulnerability and take necessary actions to mitigate the risk.

Technical summary

A race condition in OpenVPN 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1 allows remote attackers to potentially cause a server crash or leak heap memory via a use-after-free triggered during TLS session promotion.

Defensive priority

Medium

Recommended defensive actions

  • Update to a fixed version of OpenVPN
  • Refer to [ref-6](https://community.openvpn.net/Security%20Announcements/CVE-2026-40215) for security announcements and patches

Evidence notes

The CVE record [cve-org] and NVD detail [nvd] provide official information about the vulnerability.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-40215 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-40215

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-40215 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-40215

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.