CVE-2026-80520
Received Received - Intake

NULL dereference in Linux kernel OpenVPN

Publication date: 2026-08-26

Last updated on: 2026-08-26

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: ovpn: fix NULL dereference when killing missing key ovpn_crypto_kill_key assumes both crypto slots are populated and dereferences each slot before checking it. That is not guaranteed: a peer can have only one installed key, and the kill path may be asked to remove a key that is not present. Read each slot once while holding the crypto state lock, check for NULL before looking at key_id, and only replace the slot that actually matches.

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Meta Information

Published
2026-08-26
Last Modified
2026-08-26
Generated
2026-08-26
AI Q&A
2026-08-26
EPSS Evaluated
N/A
NVD
CVE-2026-80520
EUVD
EUVD-2026-66586

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
openvpn openvpn *

Helpful Resources

Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a NULL pointer dereference in the Linux kernel's OpenVPN implementation. The issue occurs in the ovpn_crypto_kill_key function, which assumes both cryptographic slots are populated but does not verify this before accessing them. A peer might only have one key installed, and attempting to remove a non-existent key triggers a crash by dereferencing a NULL pointer.

Detection Guidance

This vulnerability is specific to the Linux kernel's OpenVPN implementation and involves a NULL dereference in the ovpn_crypto_kill_key function. Detection requires checking kernel logs for crashes or errors related to OpenVPN's crypto operations. Look for messages like 'NULL pointer dereference' or 'kernel panic' in /var/log/kern.log or journalctl logs. No direct commands are provided, but monitoring kernel logs for OpenVPN-related errors is recommended.

Impact Analysis

This vulnerability could cause a system crash or denial of service if exploited. Attackers might trigger the NULL dereference by sending maliciously crafted requests to remove non-existent keys, leading to kernel panic or instability in systems running vulnerable OpenVPN versions.

Mitigation Strategies

Apply the latest Linux kernel update that includes the fix for this vulnerability. If immediate patching is not possible, consider disabling OpenVPN's crypto key management temporarily or restricting access to OpenVPN services until the patch is applied. Monitor kernel logs for signs of exploitation attempts.

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