CVE-2026-74727
Description
A flaw was found in the Linux kernel's ovpn module. A race condition can occur when an OpenVPN (ovpn) peer is removed concurrently while the system attempts to rehash it. This can lead to the peer being re-inserted into internal tables after it has been logically removed, creating a Use-After-Free (UAF) vulnerability. This flaw could allow an attacker to cause a denial of service or potentially execute arbitrary code.
Statement
A moderate-severity use-after-free flaw was found in the Linux kernel's ovpn (OpenVPN kernel module) driver. When a peer is resolved by ovpn_peer_get_by_id() or handled on the float path in ovpn_peer_endpoints_update() while only a reference count is held, a concurrent peer deletion (OVPN_CMD_PEER_DEL), keepalive expiry, or socket teardown can take ovpn->lock first and remove the peer from all internal hash tables; the subsequent rehash can then re-insert the already-removed peer, leaving hash entries linked after the peer is freed and opening a use-after-free window. An attacker able to trigger this race could cause a denial of service or, potentially, execute arbitrary code. Red Hat rates this flaw as Moderate (CVSS 3.1 score 5.5, AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) because triggering the race requires local access with privileges to perform peer-management operations and the practical impact is a loss of system availability. This differs significantly from the upstream CVE record's Critical rating of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), which assumes an unauthenticated network vector with full confidentiality and integrity impact. The ovpn module was introduced in upstream kernel version 6.16, and the vulnerable code is not present in the Red Hat Enterprise Linux 6, 7, 8, 9, and 10 kernels or the Red Hat In-Vehicle OS kernels covered by this flaw, so all Red Hat products listed here are not affected.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. No mitigation is required for the Red Hat products covered by this flaw, because the vulnerable ovpn code is not present in their kernels.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | 9.8 |
| Attack Vector | Local | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | High |
| Integrity Impact | None | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.
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