Skip to main content

Linux Kernel ksmbd EUVDEUVD-2026-45825

| CVE-2026-64140 HIGH
NULL Pointer Dereference (CWE-476)
2026-07-19 Linux GHSA-3wf5-rcm5-gfqq
Denial Of Service Linux Null Pointer Dereference Canonical
7.5
CVSS 3.1 · Vendor: Linux
Share

Severity by source

Vendor (Linux) PRIMARY
7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
vuln.today AI
4.4 MEDIUM

Crash fires only when root reads /proc/fs/ksmbd/files (mode 0400), so AV:L and PR:H; DoS-only means C:N/I:N/A:H; seconds-long window keeps AC:L.

3.1 AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
4.0 AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
SUSE
HIGH
qualitative

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

5
Analysis Generated
Jul 20, 2026 - 17:41 vuln.today
CVSS changed
Jul 20, 2026 - 15:22 NVD
7.5 (HIGH)
Patch available
Jul 19, 2026 - 17:03 EUVD
CVE Published
Jul 19, 2026 - 15:40 cve.org
UNKNOWN (no severity yet)
CVE Published
Jul 19, 2026 - 15:40 cve.org
HIGH 7.5

DescriptionCVE.org

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix null pointer dereference in proc_show_files()

When a SMB2 client opens a file with a durable v2 handle and then issues SMB2 SESSION_LOGOFF, session_fd_check() clears fp->tcon = NULL on the reconnectable file pointer but leaves the fp registered in global_ft.idr until the durable scavenger fires (up to fp->durable_timeout seconds later).

During that window any read of /proc/fs/ksmbd/files (mode 0400) panics the kernel because proc_show_files() walks global_ft.idr and unconditionally dereferences fp->tcon->id with no NULL guard.

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 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:proc_show_files+0x118/0x740 Call Trace: proc_show_files+0x118/0x740 seq_read_iter+0x4ef/0xe10 proc_reg_read_iter+0x1b7/0x280 ...

Guard the dereference. A durable-disconnected fp legitimately has no tcon; report its tree id as 0 rather than oopsing.

AnalysisAI

Kernel-panic denial of service in the Linux kernel's in-kernel SMB server (ksmbd) allows the file-pointer table to retain a durable-handle file object with a NULL tcon after a client issues SMB2 SESSION_LOGOFF; any subsequent read of /proc/fs/ksmbd/files then dereferences the NULL fp->tcon in proc_show_files() and crashes the host. Affected are kernels running ksmbd on shares configured with 'durable handles = yes'. There is no public exploit identified at time of analysis and EPSS is low (0.16%, 6th percentile), consistent with a stability/robustness bug rather than a weaponizable RCE.

Technical ContextAI

The flaw is in ksmbd, the Linux kernel's native SMB3 file-server module (CPE cpe:2.3:a:linux:linux). ksmbd tracks open files in a global IDR (global_ft.idr). When a durable v2 handle is left reconnectable and the client sends SMB2 SESSION_LOGOFF, session_fd_check() sets fp->tcon = NULL but intentionally leaves the file pointer registered so the client can reconnect, until the durable scavenger reclaims it after fp->durable_timeout seconds. The debug interface /proc/fs/ksmbd/files (mode 0400) enumerates that IDR and unconditionally dereferences fp->tcon->id. Because a durable-disconnected fp legitimately has a NULL tcon, this is a classic NULL pointer dereference (CWE-476); KASAN reports it as a null-ptr-deref / general protection fault at proc_show_files+0x118 on mainline 70390501d194. The fix adds a NULL guard, reporting tree id 0 instead of oopsing.

RemediationAI

Vendor-released patch: update to a Linux kernel including the ksmbd fix (stable commits 8eab081627b67216d1c8f638b68289b500dc9a6b and 904901561e61a2b559070b20c74a8c95491f30aa; distribution builds corresponding to 7.0.11 / 7.1 per EUVD-2026-45825). Apply your distribution's kernel update and reboot. If patching must be deferred, the most effective compensating control is to disable durable handles on ksmbd shares (set 'durable handles = no' in the share config), which removes the reconnectable-fp window at the cost of losing durable-handle resilience for clients. Alternatively, restrict or avoid reads of /proc/fs/ksmbd/files (already root-only at mode 0400) - ensure monitoring/automation does not poll this debug file while durable handles are in use - or unload the ksmbd module entirely if the in-kernel SMB server is not required, which stops all SMB serving via ksmbd. See https://git.kernel.org/stable/c/8eab081627b67216d1c8f638b68289b500dc9a6b for the patch.

More in Canonical

View all
CVE-2011-3544 CRITICAL POC
9.8 Oct 19

Oracle Java SE JDK/JRE 7 and 6 Update 27 and earlier allows remote code execution with complete system compromise throug
CVE-2019-11043 CRITICAL POC
9.8 Oct 28

In PHP versions 7.1.x below 7.1.33, 7.2.x below 7.2.24 and 7.3.x below 7.3.11 in certain configurations of FPM setup it

CVE-2014-6271 CRITICAL POC
9.8 Sep 24

GNU Bash through 4.3 processes trailing strings after function definitions in the values of environment variables, which
CVE-2013-0422 CRITICAL POC
9.8 Jan 10

Multiple vulnerabilities in Oracle Java 7 before Update 11 allow remote attackers to execute arbitrary code by (1) using
CVE-2016-3714 HIGH POC
8.4 May 05

The (1) EPHEMERAL, (2) HTTPS, (3) MVG, (4) MSL, (5) TEXT, (6) SHOW, (7) WIN, and (8) PLT coders in ImageMagick before 6.
CVE-2017-12617 HIGH POC
8.1 Oct 04

When running Apache Tomcat versions 9.0.0.M1 to 9.0.0, 8.5.0 to 8.5.22, 8.0.0.RC1 to 8.0.46 and 7.0.0 to 7.0.81 with HTT
CVE-2016-8735 CRITICAL POC
9.8 Apr 06

Remote code execution is possible with Apache Tomcat before 6.0.48, 7.x before 7.0.73, 8.x before 8.0.39, 8.5.x before 8
CVE-2014-7169 CRITICAL POC
9.8 Sep 25

GNU Bash through 4.3 bash43-025 processes trailing strings after certain malformed function definitions in the values of
CVE-2014-0160 HIGH POC
7.5 Apr 07

The (1) TLS and (2) DTLS implementations in OpenSSL 1.0.1 before 1.0.1g do not properly handle Heartbeat Extension packe
CVE-2016-5195 HIGH POC
7.0 Nov 10

Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by lev
CVE-2013-2423 LOW POC
3.7 Apr 17

Unspecified vulnerability in the Java Runtime Environment (JRE) component in Oracle Java SE 7 Update 17 and earlier, and
CVE-2023-4911 HIGH POC
7.8 Oct 03

Local privilege escalation in the GNU C Library (glibc) dynamic loader ld.so allows unprivileged local users on affected

Same weakness CWE-476 – NULL Pointer Dereference

View all
CVE-2016-0742 HIGH
7.5
CVE-2014-3470 MEDIUM
4.3
CVE-2017-3730 HIGH POC
7.5
CVE-2017-3169 CRITICAL POC
9.8
CVE-2016-4957 HIGH
7.5
CVE-2015-3194 HIGH
7.5
CVE-2026-21525 MEDIUM
6.2
CVE-2017-0016 MEDIUM
5.9

Same technique Denial Of Service

View all
CVE-2015-5119 CRITICAL POC
9.8
CVE-2011-2462 CRITICAL POC
9.8
CVE-2011-0611 HIGH POC
8.8
CVE-2012-1889 HIGH POC
8.8
CVE-2012-0507 CRITICAL POC
9.8
CVE-2014-1761 HIGH POC
7.8
CVE-2015-5122 CRITICAL POC
9.8
CVE-2011-0609 HIGH POC
7.8

Vendor StatusVendor

SUSE

Severity: Important
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 16.0 Affected

Share

EUVD-2026-45825 vulnerability details – vuln.today
Back

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy