CVE-2025-39894
7.5 · HIGHOverview
CVE-2025-39894 is a high-severity vulnerability affecting linux linux_kernel. It was published on October 1, 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:
netfilter: br_netfilter: do not check confirmed bit in br_nf_local_in() after confirm
When send a broadcast packet to a tap device, which was added to a bridge,
br_nf_local_in() is called to confirm the conntrack. If another conntrack
with the same hash value is added to the hash table, which can be
triggered by a normal packet to a non-bridge device, the below warning
may happen.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 96 at net/bridge/br_netfilter_hooks.c:632 br_nf_local_in+0x168/0x200
CPU: 1 UID: 0 PID: 96 Comm: tap_send Not tainted 6.17.0-rc2-dirty #44 PREEMPT(voluntary)
RIP: 0010:br_nf_local_in+0x168/0x200
Call Trace:
<TASK>
nf_hook_slow+0x3e/0xf0
br_pass_frame_up+0x103/0x180
br_handle_frame_finish+0x2de/0x5b0
br_nf_hook_thresh+0xc0/0x120
br_nf_pre_routing_finish+0x168/0x3a0
br_nf_pre_routing+0x237/0x5e0
br_handle_frame+0x1ec/0x3c0
__netif_receive_skb_core+
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 | >= 5.15.151, < 5.15.192 | Affected |
References
Frequently Asked Questions
What is CVE-2025-39894?
CVE-2025-39894 is a high-severity vulnerability affecting linux linux_kernel. It was published on October 1, 2025 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2025-39894?
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-2025-39894?
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-2025-39894?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-39894 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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