CVE Catalog

CVE-2026-64137

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.13%

3th percentile - higher than 3% of all known CVEs

Summary

In the Linux kernel, a vulnerability was found in the CIFS SWN netlink implementation. Missing capability flags for generic netlink operations allow any local process to send RESOURCE_CHANGE or CLIENT_MOVE notifications to the in-kernel witness handler. Additionally, the multicast group lacks protection, enabling unprivileged processes to join and receive registration messages containing username, domain, and password for NTLM-authenticated mounts.

Risk Assessment

The risk involves potential leakage of sensitive credentials (username, domain, password) to a local unprivileged attacker, which could lead to privilege escalation or unauthorized access to network resources.

Recommendation

Immediately update the Linux kernel to a version that requires CAP_NET_ADMIN for SWN_NOTIFY operations and for joining the SWN multicast group.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: smb: client: require net admin for CIFS SWN netlink CIFS_GENL_CMD_SWN_NOTIFY is the userspace witness-notify command. The intended sender is the cifs.witness helper, but the generic-netlink operation currently has no capability flag, so any local process can send RESOURCE_CHANGE or CLIENT_MOVE notifications to the in-kernel witness handler. The same family exposes CIFS_GENL_MCGRP_SWN without multicast-group capability flags. Register messages sent to that group include the witness registration id and, for NTLM-authenticated mounts, the username, domain, and password attributes copied from the CIFS session. An unprivileged local process should not be able to join that group and receive those messages. Require CAP_NET_ADMIN for incoming SWN_NOTIFY commands with GENL_ADMIN_PERM, and require CAP_NET_ADMIN over the network namespace for joining the SWN multicast group with GENL_MCAST_CAP_NET_ADMIN. The cifs.witness service runs with the privileges needed for both operations.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS