VDB-305130 · CVE-2025-22077 · Nessus 238279

Linux Kernel up to 6.6.86/6.12.22/6.13.10/6.14.1 SMB Client get_net/put_net reference count

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5.0	$0-$5k	0.00

Summaryinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.6.86/6.12.22/6.13.10/6.14.1. Affected by this issue is the function get_net/put_net of the component SMB Client. The manipulation results in reference count. This vulnerability is known as CVE-2025-22077. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.6.86/6.12.22/6.13.10/6.14.1. Affected is the function get_net/put_net of the component SMB Client. The manipulation with an unknown input leads to a reference count vulnerability. CWE is classifying the issue as CWE-911. The product uses a reference count to manage a resource, but it does not update or incorrectly updates the reference count. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: Revert "smb: client: fix TCP timers deadlock after rmmod" This reverts commit e9f2517a3e18a54a3943c098d2226b245d488801. Commit e9f2517a3e18 ("smb: client: fix TCP timers deadlock after rmmod") is intended to fix a null-ptr-deref in LOCKDEP, which is mentioned as CVE-2024-54680, but is actually did not fix anything; The issue can be reproduced on top of it. [0] Also, it reverted the change by commit ef7134c7fc48 ("smb: client: Fix use-after-free of network namespace.") and introduced a real issue by reviving the kernel TCP socket. When a reconnect happens for a CIFS connection, the socket state transitions to FIN_WAIT_1. Then, inet_csk_clear_xmit_timers_sync() in tcp_close() stops all timers for the socket. If an incoming FIN packet is lost, the socket will stay at FIN_WAIT_1 forever, and such sockets could be leaked up to net.ipv4.tcp_max_orphans. Usually, FIN can be retransmitted by the peer, but if the peer aborts the connection, the issue comes into reality. I warned about this privately by pointing out the exact report [1], but the bogus fix was finally merged. So, we should not stop the timers to finally kill the connection on our side in that case, meaning we must not use a kernel socket for TCP whose sk->sk_net_refcnt is 0. The kernel socket does not have a reference to its netns to make it possible to tear down netns without cleaning up every resource in it. For example, tunnel devices use a UDP socket internally, but we can destroy netns without removing such devices and let it complete during exit. Otherwise, netns would be leaked when the last application died. However, this is problematic for TCP sockets because TCP has timers to close the connection gracefully even after the socket is close()d. The lifetime of the socket and its netns is different from the lifetime of the underlying connection. If the socket user does not maintain the netns lifetime, the timer could be fired after the socket is close()d and its netns is freed up, resulting in use-after-free. Actually, we have seen so many similar issues and converted such sockets to have a reference to netns. That's why I converted the CIFS client socket to have a reference to netns (sk->sk_net_refcnt == 1), which is somehow mentioned as out-of-scope of CIFS and technically wrong in e9f2517a3e18, but **is in-scope and right fix**. Regarding the LOCKDEP issue, we can prevent the module unload by bumping the module refcount when switching the LOCKDDEP key in sock_lock_init_class_and_name(). [2] For a while, let's revert the bogus fix. Note that now we can use sk_net_refcnt_upgrade() for the socket conversion, but I'll do so later separately to make backport easy.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2025-22077 since 12/29/2024. The exploitability is told to be difficult. Technical details are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 238279 (Amazon Linux 2023 : bpftool, kernel6.12, kernel6.12-modules-extra (ALAS2023-2025-995)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.87, 6.12.23, 6.13.11, 6.14.2 or 6.15-rc1 eliminates this vulnerability. Applying the patch c6b6b8dcef4adf8ee4e439bb97e74106096c71b8/7d8dfc27d90d41627c0d6ada97ed0ab57b3dae25/961755d0055e0e96d1849cc0425da966c8a64e53/476617a4ca0123f0df677d547a82a110c27c8c74/4e7f1644f2ac6d01dc584f6301c3b1d5aac4eaef is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (238279) and CERT Bund (WID-SEC-2025-0844). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

Google Container-Optimized OS
Debian Linux
Amazon Linux 2
Red Hat Enterprise Linux
Ubuntu Linux
SUSE Linux
Oracle Linux
SUSE openSUSE
RESF Rocky Linux
Open Source Linux Kernel
Dell Avamar
SolarWinds Security Event Manager
Dell NetWorker
Dell Secure Connect Gateway
IBM QRadar SIEM

Productinfo

Type

Operating System

Vendor

Linux

Name

Kernel

Version

License

open-source

Website

Vendor: https://www.kernel.org/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.1
VulDB Meta Temp Score: 5.0

VulDB Base Score: 4.8
VulDB Temp Score: 4.6
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Reference count
CWE: CWE-911 / CWE-664
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍