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Linux Kernel EUVDEUVD-2026-59406

| CVE-2026-74259 HIGH
2026-08-15 Linux GHSA-48v3-jvq8-5vjp
8.4
CVSS 3.1 · Vendor: Linux
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Severity by source

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

Mounting CIFS and creating network namespaces require at least low privileges (PR:L); impact is kernel panic (A:H) with no demonstrated confidentiality or integrity compromise.

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

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

5
Analysis Generated
Aug 17, 2026 - 10:02 vuln.today
CVSS changed
Aug 17, 2026 - 06:22 NVD
8.4 (HIGH)
Patch available
Aug 15, 2026 - 07:20 EUVD
CVE Published
Aug 15, 2026 - 05:57 cve.org
UNKNOWN (no severity yet)
CVE Published
Aug 15, 2026 - 05:57 cve.org
HIGH 8.4

DescriptionCVE.org

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

cifs: remove all cifs files before kill super

Cifs files may be put into fileinfo_put_wq during umounting cifs. After umount done, cifsFileInfo_put_final is called, which cause following BUG:

BUG: kernel NULL pointer dereference, address: 0000000000000000 ... [ 134.222152] list_lru_add+0x64/0x1a0 [ 134.222399] ? cifs_put_tcon+0x171/0x340 [cifs] [ 134.222772] d_lru_add+0x44/0x60 [ 134.222997] dput+0x1fc/0x210 [ 134.223213] cifsFileInfo_put_final+0x11a/0x140 [cifs] [ 134.223576] process_one_work+0x17c/0x320 [ 134.223843] worker_thread+0x188/0x280 [ 134.224084] ? __pfx_worker_thread+0x10/0x10 [ 134.224366] kthread+0xcc/0x100 [ 134.224576] ? __pfx_kthread+0x10/0x10 [ 134.224827] ret_from_fork+0x30/0x50 [ 134.225063] ? __pfx_kthread+0x10/0x10 [ 134.225328] ret_from_fork_asm+0x1b/0x30

This can be reproduce by following: unshare -n bash -c " mkdir -p ${CIFS_MNT} ip netns attach root 1 ip link add eth0 type veth peer veth0 netns root ip link set eth0 up ip -n root link set veth0 up ip addr add 192.168.0.2/24 dev eth0 ip -n root addr add 192.168.0.1/24 dev veth0 ip route add default via 192.168.0.1 dev eth0 ip netns exec root sysctl net.ipv4.ip_forward=1 ip netns exec root iptables -t nat -A POSTROUTING -s 192.168.0.2 -o ${DEV} -j MASQUERADE mount -t cifs ${CIFS_PATH} ${CIFS_MNT} -o vers=3.0,sec=ntlmssp,credentials=${CIFS_CRED},rsize=65536,wsize=65536,cache=none,echo_interval=1 touch ${CIFS_MNT}/a.txt ip netns exec root iptables -t nat -D POSTROUTING -s 192.168.0.2 -o ${DEV} -j MASQUERADE " umount ${CIFS_MNT}

AnalysisAI

The Linux kernel CIFS client driver crashes with a NULL pointer dereference when a filesystem is unmounted while CIFS file objects remain queued in the fileinfo_put_wq work queue. Multiple stable branches from 6.1 through 6.19 are affected, with patched versions released across all active stable trees. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Recon
Create network namespace and mount CIFS share
Delivery
Open files on mounted CIFS share
Exploit
Disrupt network path to CIFS server (e.g., delete NAT rules)
Install
Initiate umount while file objects queue in fileinfo_put_wq
C2
Superblock and tcon freed by kill_super
Execute
Deferred worker executes cifsFileInfo_put_final on freed tcon
Impact
NULL pointer dereference in list_lru_add triggers kernel panic

Vulnerability AssessmentAI

Exploitation Exploitation requires: (1) permission to create user or network namespaces - either unprivileged_userns_clone=1 (default on many distributions) or CAP_NET_ADMIN; (2) the ability to mount a CIFS/SMB filesystem (typically root, or a user with the mount capability); (3) at least one file open on the CIFS mount at the time of network disruption. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment Real-world risk is low despite the elevated NVD CVSS score of 8.4. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario A local user with network namespace creation rights mounts a CIFS share inside a new network namespace, opens files on the share, then deliberately tears down the NAT rules forwarding traffic to the CIFS server, forcing the kernel CIFS client to queue file cleanup work in fileinfo_put_wq. The user then unmounts the filesystem; the superblock and tcon are freed, but the queued worker subsequently calls cifsFileInfo_put_final against the freed tcon, triggering a NULL pointer dereference in list_lru_add and a kernel panic. …
Remediation Upgrade to a patched stable kernel release: Linux 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5, or 7.2-rc1, selecting the branch appropriate to the running system. … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours: Identify all systems running Linux kernel versions 6.1 through 6.19, prioritizing production infrastructure with active CIFS mounts for risk assessment. …

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Threat intelligence, references, and detailed analysis are available after sign-in.

Vendor StatusVendor

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EUVD-2026-59406 vulnerability details – vuln.today

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