CVE-2025-39874
5.5 · MEDIUMOverview
CVE-2025-39874 is a medium-severity vulnerability affecting linux linux_kernel. It was published on September 23, 2025 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
In the Linux kernel, the following vulnerability has been resolved:
macsec: sync features on RTM_NEWLINK
Syzkaller managed to lock the lower device via ETHTOOL_SFEATURES:
netdev_lock include/linux/netdevice.h:2761 [inline]
netdev_lock_ops include/net/netdev_lock.h:42 [inline]
netdev_sync_lower_features net/core/dev.c:10649 [inline]
__netdev_update_features+0xcb1/0x1be0 net/core/dev.c:10819
netdev_update_features+0x6d/0xe0 net/core/dev.c:10876
macsec_notify+0x2f5/0x660 drivers/net/macsec.c:4533
notifier_call_chain+0x1b3/0x3e0 kernel/notifier.c:85
call_netdevice_notifiers_extack net/core/dev.c:2267 [inline]
call_netdevice_notifiers net/core/dev.c:2281 [inline]
netdev_features_change+0x85/0xc0 net/core/dev.c:1570
__dev_ethtool net/ethtool/ioctl.c:3469 [inline]
dev_ethtool+0x1536/0x19b0 net/ethtool/ioctl.c:3502
dev_ioctl+0x392/0x1150 net/core/dev_ioctl.c:759
It happens because lower features are out of sync with the upper:
__dev_ethtool (real_dev)
netdev_lock_ops(re
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 | >= 6.15, < 6.16.8 | Affected |
Frequently Asked Questions
What is CVE-2025-39874?
CVE-2025-39874 is a medium-severity vulnerability affecting linux linux_kernel. It was published on September 23, 2025 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2025-39874?
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2025-39874?
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-2025-39874?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-39874 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.
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