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High severity7.8NVD Advisory· Published Feb 27, 2025· Updated May 12, 2026

CVE-2025-21761

CVE-2025-21761

Description

In the Linux kernel, the following vulnerability has been resolved:

openvswitch: use RCU protection in ovs_vport_cmd_fill_info()

ovs_vport_cmd_fill_info() can be called without RTNL or RCU.

Use RCU protection and dev_net_rcu() to avoid potential UAF.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

A use-after-free vulnerability in Linux kernel's openvswitch module due to missing RCU protection in ovs_vport_cmd_fill_info() could allow local privilege escalation.

Vulnerability

Overview

The Linux kernel's openvswitch module contains a use-after-free (UAF) vulnerability in the ovs_vport_cmd_fill_info() function. This function can be invoked without holding the RCU read lock or the RTNL mutex, leading to a race condition where the network namespace (net) pointer obtained via dev_net() may be freed while still in use [1]. The fix introduces RCU protection and replaces dev_net() with dev_net_rcu() to ensure safe access [2][3][4].

Exploitation

Conditions

An attacker with local access and the ability to trigger openvswitch operations (e.g., via netlink messages) could exploit this race. No special privileges beyond a local user account are required if the attacker can manipulate vport operations while the device or namespace is being removed. The vulnerability is classified as High severity with a CVSS v3 score of 7.8, indicating a significant risk of local privilege escalation.

Impact

Successful exploitation could allow an attacker to corrupt kernel memory, potentially leading to arbitrary code execution with kernel privileges. This could result in full system compromise, including data disclosure, denial of service, or persistent access.

Mitigation

The fix has been backported to stable kernel releases. Users should update to the latest patched kernel version. The Siemens advisory (SSA-265688) lists this CVE among many affecting the SIMATIC S7-1500 TM MFP - GNU/Linux subsystem, recommending updates for affected products [1].

References
  1. SSA-265688
  2. Making sure you're not a bot!
  3. Making sure you're not a bot!
  4. Making sure you're not a bot!

AI Insight generated on May 20, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.

Affected products

156

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

11

News mentions

0

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