CVE-2026-68342
Received Received - Intake

Use-After-Free in OpenVPN Kernel Module

Vulnerability report for CVE-2026-68342, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-10

Last updated on: 2026-08-17

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: ovpn: avoid putting unrelated P2P peer on socket release ovpn_peer_release_p2p() is called when an OVPN UDP socket is being destroyed. It checks the currently published P2P peer and releases it only if that peer still uses the socket being destroyed. A peer replacement can publish a new peer before the old UDP socket is destroyed. When the old socket destruction path runs afterwards, ovpn_peer_release_p2p() observes the new peer through ovpn->peer. Since the new peer uses a different socket, the function takes the socket mismatch branch. That branch still calls ovpn_peer_put(peer). At this point, however, peer is the currently published replacement peer, not the peer associated with the socket being destroyed. Dropping its reference can free it while ovpn->peer still points to it, leading to later use-after-free accesses from the peer and socket cleanup paths. KASAN reports this as a slab-use-after-free on the kmalloc-1k ovpn_peer object. In the reproducer, the object is allocated from ovpn_peer_new() via ovpn_nl_peer_new_doit(), and freed through ovpn_peer_release_rcu() from RCU callback processing. Observed access sites include ovpn_peer_remove(), ovpn_socket_release(), ovpn_nl_peer_del_notify(), and unlock_ovpn(). Fix this by returning from the socket mismatch branch without putting the peer.

CVSS Scores

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Meta Information

Published
2026-08-10
Last Modified
2026-08-17
Generated
2026-08-30
AI Q&A
2026-08-10
EPSS Evaluated
2026-08-29
NVD
EUVD

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

Attack-Flow Graph

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Executive Summary

This is a use-after-free vulnerability in the Linux kernel's OpenVPN (ovpn) implementation. It occurs when a peer replacement publishes a new peer before the old UDP socket is destroyed. The cleanup function incorrectly drops a reference to the new peer, causing it to be freed while still in use. This leads to memory corruption and potential system crashes.

Detection Guidance

This vulnerability is specific to the Linux kernel's OpenVPN implementation and may not have direct detection commands. Monitor kernel logs for slab-use-after-free errors related to ovpn_peer objects. Check for crashes or unexpected behavior in OpenVPN services.

Impact Analysis

This vulnerability could allow an attacker to cause a denial-of-service (system crash) or potentially execute arbitrary code on affected systems. It may also lead to data corruption or unauthorized access if exploited in a multi-tenant environment.

Compliance Impact

This vulnerability is a use-after-free issue in the Linux kernel's OpenVPN implementation that could lead to memory corruption or crashes. It does not directly affect compliance with standards like GDPR or HIPAA, as those focus on data protection, privacy, and security controls rather than kernel-level memory management flaws.

Mitigation Strategies

Apply the Linux kernel patch that resolves this issue. Update your OpenVPN and kernel to the latest stable versions. Restart OpenVPN services to ensure the fix is active. Monitor system stability and logs for any signs of the vulnerability.

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