CyberSecBulletin
CVE-2026-64141NVD status: Analyzed

Linux: NULL Pointer Dereference

Published Updated By the CyberSecBulletin desk

CVE-2026-64141 is a high-severity NULL pointer dereference vulnerability in Linux, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions e43cb36d4d7827710cfcd48e95e29a507f0d87be, 0836081b394ca074d1b910f2b990ff7b4b4404c7, cd5c1b75d2f454f625d7dc55bd3ae21d0855f6ad as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.63% chance of exploitation within 30 days, higher than 51% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to e43cb36d4d7827710cfcd48e95e29a507f0d87be or 0836081b394ca074d1b910f2b990ff7b4b4404c7 or cd5c1b75d2f454f625d7dc55bd3ae21d0855f6ad or af86896ca3239e25a6bd7d352213371265073d38, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 6.6.142 or 6.12.92 or 6.18.34 or 7.0.11, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux8df4bcdb0a4232192b2445256c39b787d58ef14d up to, but not including, e43cb36d4d7827710cfcd48e95e29a507f0d87be; c8efcc786146a951091588e5fa7e3c754850cb3c up to, but not including, 0836081b394ca074d1b910f2b990ff7b4b4404c7; c8efcc786146a951091588e5fa7e3c754850cb3c up to, but not including, cd5c1b75d2f454f625d7dc55bd3ae21d0855f6ad; c8efcc786146a951091588e5fa7e3c754850cb3c up to, but not including, af86896ca3239e25a6bd7d352213371265073d38; c8efcc786146a951091588e5fa7e3c754850cb3c up to, but not including, 4b83cbc4c15f09b000cc06f033f64b0824b6dc87; 6.6.32 up to, but not including, 6.6.142; 6.9e43cb36d4d7827710cfcd48e95e29a507f0d87be, 0836081b394ca074d1b910f2b990ff7b4b4404c7, cd5c1b75d2f454f625d7dc55bd3ae21d0855f6ad, af86896ca3239e25a6bd7d352213371265073d38, 4b83cbc4c15f09b000cc06f033f64b0824b6dc87, 6.6.142
LinuxLinux Kernel6.6.32 up to, but not including, 6.6.142; 6.9 up to, but not including, 6.12.92; 6.13 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 7.16.6.142, 6.12.92, 6.18.34, 7.0.11

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA.

Official description

In 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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: NULL Pointer Dereference

The product dereferences a pointer that it expects to be valid but is NULL.

How developers prevent this class of flaw

  • For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
  • Select a programming language that is not susceptible to these issues.
  • Check the results of all functions that return a value and verify that the value is non-null before acting upon it.

More NULL Pointer Dereference vulnerabilities (CWE-476)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Recent NULL Pointer Dereference vulnerabilities

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