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Fencer Vulns
high 7.5

CVE-2025-38379 json

smb: client: fix warning when reconnecting channel

published 2025-07-25 15 mo ago modified 2026-08-05 3 mo ago also EUVD-2025-22624

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 35%
public exploits
0
none known

Summary

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

smb: client: fix warning when reconnecting channel

When reconnecting a channel in smb2_reconnect_server(), a dummy tcon is passed down to smb2_reconnect() with ->query_interface uninitialized, so we can't call queue_delayed_work() on it.

Fix the following warning by ensuring that we're queueing the delayed worker from correct tcon.

WARNING: CPU: 4 PID: 1126 at kernel/workqueue.c:2498 __queue_delayed_work+0x1d2/0x200 Modules linked in: cifs cifs_arc4 nls_ucs2_utils cifs_md4 [last unloaded: cifs] CPU: 4 UID: 0 PID: 1126 Comm: kworker/4:0 Not tainted 6.16.0-rc3 #5 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-4.fc42 04/01/2014 Workqueue: cifsiod smb2_reconnect_server [cifs] RIP: 0010:__queue_delayed_work+0x1d2/0x200 Code: 41 5e 41 5f e9 7f ee ff ff 90 0f 0b 90 e9 5d ff ff ff bf 02 00 00 00 e8 6c f3 07 00 89 c3 eb bd 90 0f 0b 90 e9 57 f> 0b 90 e9 65 fe ff ff 90 0f 0b 90 e9 72 fe ff ff 90 0f 0b 90 e9 RSP: 0018:ffffc900014afad8 EFLAGS: 00010003 RAX: 0000000000000000 RBX: ffff888124d99988 RCX: ffffffff81399cc1 RDX: dffffc0000000000 RSI: ffff888114326e00 RDI: ffff888124d999f0 RBP: 000000000000ea60 R08: 0000000000000001 R09: ffffed10249b3331 R10: ffff888124d9998f R11: 0000000000000004 R12: 0000000000000040 R13: ffff888114326e00 R14: ffff888124d999d8 R15: ffff888114939020 FS: 0000000000000000(0000) GS:ffff88829f7fe000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe7a2b4038 CR3: 0000000120a6f000 CR4: 0000000000750ef0 PKRU: 55555554 Call Trace: <TASK> queue_delayed_work_on+0xb4/0xc0 smb2_reconnect+0xb22/0xf50 [cifs] smb2_reconnect_server+0x413/0xd40 [cifs] ? __pfx_smb2_reconnect_server+0x10/0x10 [cifs] ? local_clock_noinstr+0xd/0xd0 ? local_clock+0x15/0x30 ? lock_release+0x29b/0x390 process_one_work+0x4c5/0xa10 ? __pfx_process_one_work+0x10/0x10 ? __list_add_valid_or_report+0x37/0x120 worker_thread+0x2f1/0x5a0 ? __kthread_parkme+0xde/0x100 ? __pfx_worker_thread+0x10/0x10 kthread+0x1fe/0x380 ? kthread+0x10f/0x380 ? __pfx_kthread+0x10/0x10 ? local_clock_noinstr+0xd/0xd0 ? ret_from_fork+0x1b/0x1f0 ? local_clock+0x15/0x30 ? lock_release+0x29b/0x390 ? rcu_is_watching+0x20/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x15b/0x1f0 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> irq event stamp: 1116206 hardirqs last enabled at (1116205): [<ffffffff8143af42>] __up_console_sem+0x52/0x60 hardirqs last disabled at (1116206): [<ffffffff81399f0e>] queue_delayed_work_on+0x6e/0xc0 softirqs last enabled at (1116138): [<ffffffffc04562fd>] __smb_send_rqst+0x42d/0x950 [cifs] softirqs last disabled at (1116136): [<ffffffff823d35e1>] release_sock+0x21/0xf0

Patch / fix

  • Linux Linux 6.6.97, 6.12.37, 6.15.6
  • linux Debian 14, Debian 13 6.12.37-1

debian advisories DEBIAN-CVE-2025-38379

  • kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-40.1
  • kernel-rt Linux Micro 6.2 6.12.0-160000.26.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.26.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1.160000.2.7
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.26.1

suse advisories SUSE-SU-2026:20845-1SUSE-SU-2026:20876-1SUSE-SU-2026:20555-1SUSE-SU-2026:20599-1SUSE-SU-2026:20615-1SUSE-SU-2026:20570-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.26.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.26.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.26.1

opensuse advisories openSUSE-SU-2026:20287-1

  • kernel Azure Linux 3.0 6.6.104.2-1

azure linux advisories AZL-65780

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-38379 updated cvss 5.5

kernel: Linux kernel SMB client: Denial of Service via uninitialized object during channel reconnection

  • Red Hat Enterprise Linux 10 kernel
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.41% chance of exploitation in the next 30 days, higher than 35% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.