ksmbd: fix null pointer dereference in compare_guid_key()

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Summary

CVECVE-2026-64141
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: ksmbd: fix null pointer dereference in compare_guid_key() session_fd_check() walks the per-inode m_op_list during durable-handle session teardown and sets op->conn = NULL for every opinfo whose conn matched the closing session's connection. The matching opinfo, however, stays linked in its per-ClientGuid lease_table_list entry's lb->lease_list because destroy_lease_table() only runs on full TCP-connection teardown, not on SESSION_LOGOFF. If the same TCP connection then negotiates a fresh session with the same ClientGuid (ClientGuid is bound to NEGOTIATE, not the session, and is unchanged across LOGOFF + SETUP) and issues a SMB2 CREATE with a lease context on a different inode, find_same_lease_key() walks lb->lease_list, reaches the stale opinfo, and calls compare_guid_key(), which unconditionally dereferences opinfo->conn->ClientGUID. The conn pointer is NULL and the kernel panics. Reproducer requires only a successful SMB2 SESSION_SETUP and a share configured with 'durable handles = yes'. KASAN report on mainline 70390501d194: general protection fault, probably for non-canonical address 0xdffffc0000000069: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000348-0x000000000000034f] Workqueue: ksmbd-io handle_ksmbd_work RIP: 0010:bcmp+0x5b/0x230 Call Trace: compare_guid_key+0x4b/0xd0 find_same_lease_key+0x324/0x690 smb2_open+0x6aea/0x8e60 handle_ksmbd_work+0x796/0xee0 ... Faulting address 0x348 is the offset of ClientGUID within struct ksmbd_conn, confirming opinfo->conn was NULL. Read opinfo->conn once and bail out if it has been cleared by a concurrent session_fd_check(). A half-detached opinfo cannot be the owner of an active lease, so returning 0 is the correct match result.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 8df4bcdb0a4232192b2445256c39b787d58ef14d e43cb36d4d7827710cfcd48e95e29a507f0d87be git Not specified
CNA Linux Linux affected c8efcc786146a951091588e5fa7e3c754850cb3c 0836081b394ca074d1b910f2b990ff7b4b4404c7 git Not specified
CNA Linux Linux affected c8efcc786146a951091588e5fa7e3c754850cb3c cd5c1b75d2f454f625d7dc55bd3ae21d0855f6ad git Not specified
CNA Linux Linux affected c8efcc786146a951091588e5fa7e3c754850cb3c af86896ca3239e25a6bd7d352213371265073d38 git Not specified
CNA Linux Linux affected c8efcc786146a951091588e5fa7e3c754850cb3c 4b83cbc4c15f09b000cc06f033f64b0824b6dc87 git Not specified
CNA Linux Linux affected 6.6.32 6.6.142 semver Not specified
CNA Linux Linux affected 6.9 Not specified
CNA Linux Linux unaffected 6.9 semver Not specified
CNA Linux Linux unaffected 6.6.142 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/cd5c1b75d2f454f625d7dc55bd3ae21d0855f6ad 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4b83cbc4c15f09b000cc06f033f64b0824b6dc87 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0836081b394ca074d1b910f2b990ff7b4b4404c7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e43cb36d4d7827710cfcd48e95e29a507f0d87be 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/af86896ca3239e25a6bd7d352213371265073d38 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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