CVE-2026-74283

Received Received - Intake

TIPCv2 Netlink Privilege Escalation in Linux Kernel

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: tipc: require net admin for TIPCv2 netlink mutators TIPCv2 registers mutating generic-netlink operations without admin permission flags. Generic netlink only checks CAP_NET_ADMIN when an operation sets GENL_ADMIN_PERM or GENL_UNS_ADMIN_PERM, so a local unprivileged process can currently change TIPC state through commands such as TIPC_NL_NET_SET, TIPC_NL_KEY_SET, TIPC_NL_KEY_FLUSH, and bearer enable/disable. The legacy TIPC netlink API already checks netlink_net_capable(..., CAP_NET_ADMIN) for administrative commands. Give the TIPCv2 mutators the equivalent generic-netlink gate. Use GENL_UNS_ADMIN_PERM, which maps to the same namespace-aware CAP_NET_ADMIN check that netlink_net_capable() performs, so the behaviour matches the legacy path and keeps working for CAP_NET_ADMIN holders in a non-initial user namespace (containers). A QEMU/KASAN repro run as uid/gid 65534 with zero effective capabilities previously succeeded in changing the network id and node identity, setting and flushing key material, and enabling/disabling a UDP bearer. With this patch applied the same operations fail with -EPERM.

CVSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-17

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-74283

EUVD

EUVD-2026-59430

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves TIPCv2 (Transparent Inter-Process Communication version 2) registering netlink operations that modify network state without requiring administrative permissions. Normally, generic-netlink operations need CAP_NET_ADMIN to make changes, but TIPCv2 bypasses this check, allowing unprivileged local users to alter TIPC settings like network IDs, node identities, keys, and bearer states.

Detection Guidance

This vulnerability can be detected by checking if unprivileged users can modify TIPC network settings. Inspect kernel logs for unauthorized TIPC state changes or failed CAP_NET_ADMIN checks. Commands like 'dmesg | grep TIPC' or 'journalctl -k | grep TIPC' may reveal suspicious activity. Ensure TIPCv2 operations require admin privileges.

Impact Analysis

An attacker with local access could exploit this to disrupt network services, reconfigure TIPC settings, or bypass security controls. For example, they could disable network bearers or change keys, potentially causing denial-of-service or unauthorized network access. Systems using TIPC for communication are most at risk.

Compliance Impact

This vulnerability could violate compliance requirements that mandate strict access controls for network configuration changes, such as those in GDPR (data protection) or HIPAA (healthcare data security). Unauthorized modifications to network settings may lead to data breaches or loss of auditability, risking non-compliance with these standards.

Mitigation Strategies

Apply the Linux kernel patch that enforces GENL_UNS_ADMIN_PERM for TIPCv2 operations. Update to a kernel version containing the fix. Restrict access to CAP_NET_ADMIN capabilities in containers. Monitor for unauthorized TIPC changes post-patch.

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