CVE-2026-12996

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Use-After-Free in OpenVPN

Publication date: 2026-07-30

Last updated on: 2026-07-30

Assigner: OpenVPN Inc.

Description

A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote authenticated peers to potentially cause a denial of service or leak memory via crafted packets during TLS session promotion or expiry

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-07-30

Last Modified

2026-07-30

Generated

2026-07-31

AI Q&A

2026-07-31

EPSS Evaluated

N/A

NVD

CVE-2026-12996

EUVD

EUVD-2026-51239

Affected Vendors & Products

Vendor	Product	Version / Range
openvpn	openvpn	From 2.6.0 (inc) to 2.6.20 (inc)
openvpn	openvpn	From 2.7_alpha1 (inc) to 2.7.4 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-125	The product reads data past the end, or before the beginning, of the intended buffer.
CWE-416	The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

Executive Summary

This vulnerability is a use-after-free issue in OpenVPN versions 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4. It allows remote authenticated peers to cause a denial of service or memory leaks by sending specially crafted packets during TLS session promotion or expiry.

Detection Guidance

Detecting this vulnerability requires monitoring for crashes or memory leaks in OpenVPN processes. Check OpenVPN logs for segmentation faults or unusual memory usage patterns. Use system monitoring tools like 'top' or 'htop' to observe OpenVPN process behavior during TLS session promotion or expiry. No specific commands are provided in the context.

Impact Analysis

If exploited, this vulnerability could lead to service disruption by crashing the OpenVPN server or leaking sensitive memory contents. It requires an attacker to be an authenticated peer, limiting the attack surface but still posing risks to availability and confidentiality.

Compliance Impact

This vulnerability may impact compliance with GDPR and HIPAA by potentially allowing unauthorized access to sensitive data through memory leaks or denial of service during VPN operations. OpenVPN is commonly used to secure communications, and such flaws could compromise data integrity and confidentiality.

Mitigation Strategies

Upgrade OpenVPN to a version beyond 2.6.20 or 2.7.4 where this use-after-free issue is fixed. Monitor network traffic for unusual patterns that may indicate exploitation attempts.

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