smb: client: require net admin for CIFS SWN netlink

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Summary

CVECVE-2026-64137
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-19 16:17:55 UTC
Updated2026-07-19 16:17:55 UTC
DescriptionIn 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.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 9cf7eb8919344932f909b2fac76296f7656fda8d git Not specified
CNA Linux Linux affected fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 9919021a3b7974ae66a5f9915e3a48c10cfd409b git Not specified
CNA Linux Linux affected fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 969bc6370334a5b4720c5470783295d6484bbc95 git Not specified
CNA Linux Linux affected fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 a3238b09c58f323e40743ce174cd0ab81b5c09ed git Not specified
CNA Linux Linux affected fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 a8d17d22db591099519a89f14dd24810daba74c3 git Not specified
CNA Linux Linux affected fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 c2397b93fbb6f44a788fff30f99be2c20cc5e50f git Not specified
CNA Linux Linux affected fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 d1ebfce2c1d161186a82e77590bf7da2ea1bce91 git Not specified
CNA Linux Linux affected 5.11 Not specified
CNA Linux Linux unaffected 5.11 semver Not specified
CNA Linux Linux unaffected 5.15.210 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.176 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.143 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.92 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.34 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.11 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/a3238b09c58f323e40743ce174cd0ab81b5c09ed 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a8d17d22db591099519a89f14dd24810daba74c3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9cf7eb8919344932f909b2fac76296f7656fda8d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c2397b93fbb6f44a788fff30f99be2c20cc5e50f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/969bc6370334a5b4720c5470783295d6484bbc95 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9919021a3b7974ae66a5f9915e3a48c10cfd409b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/d1ebfce2c1d161186a82e77590bf7da2ea1bce91 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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