CVE-2025-40090
7.5 · HIGHOverview
CVE-2025-40090 is a high-severity vulnerability affecting linux linux_kernel. It was published on October 30, 2025 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix recursive locking in RPC handle list access
Since commit 305853cce3794 ("ksmbd: Fix race condition in RPC handle list
access"), ksmbd_session_rpc_method() attempts to lock sess->rpc_lock.
This causes hung connections / tasks when a client attempts to open
a named pipe. Using Samba's rpcclient tool:
$ rpcclient //192.168.1.254 -U user%password
$ rpcclient $> srvinfo
<connection hung here>
Kernel side:
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:0 state:D stack:0 pid:5021 tgid:5021 ppid:2 flags:0x00200000
Workqueue: ksmbd-io handle_ksmbd_work
Call trace:
__schedule from schedule+0x3c/0x58
schedule from schedule_preempt_disabled+0xc/0x10
schedule_preempt_disabled from rwsem_down_read_slowpath+0x1b0/0x1d8
rwsem_down_read_slowpath from down_read+0x28/0x30
down_read from ksmbd_session_rpc_method+0x18/0x3c
ksmbd_session_rpc_method from ksmbd_r
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linux | linux_kernel | >= 6.12.53, < 6.12.55 | Affected |
References
Frequently Asked Questions
What is CVE-2025-40090?
CVE-2025-40090 is a high-severity vulnerability affecting linux linux_kernel. It was published on October 30, 2025 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2025-40090?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2025-40090?
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-40090?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-40090 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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