# CVE-2025-39874: linux: In the Linux kernel, the following vulnerability has been resolved: macsec: sync features on RTM_NEWLINK Syzkaller... CVE-2025-39874 is fixed in 36 products on 1 platform, first by DEBIAN-CVE-2025-39874, released September 23, 2025. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2025-39874 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0013 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Sep 23, 2025 ## 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(real_dev) ETHTOOL_SFEATURES __netdev_features_change netdev_sync_upper_features disable LRO on the lower if (old_features != dev->features) netdev_features_change fires NETDEV_FEAT_CHANGE macsec_notify NETDEV_FEAT_CHANGE netdev_update_features (for each macsec dev) netdev_sync_lower_features if (upper_features != lower_features) netdev_lock_ops(lower) # lower == real_dev stuck ... netdev_unlock_ops(real_dev) Per commit af5f54b0ef9e ("net: Lock lower level devices when updating features"), we elide the lock/unlock when the upper and lower features are synced. Makes sure the lower (real_dev) has proper features after the macsec link has been created. This makes sure we never hit the situation where we need to sync upper flags to the lower. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | kernel-uek ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-core ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-core ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-core ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-core ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-devel ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-devel ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-core ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-core ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-deprecated ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-deprecated ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-desktop ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-desktop ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-extra ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-extra ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-extra-netfilter ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-extra-netfilter ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-usb ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-usb ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-wireless ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-debug-modules-wireless ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-devel ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-devel ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-doc ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-doc ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-core ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-core ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-deprecated ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-deprecated ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-desktop ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-desktop ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-extra ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-extra ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-extra-netfilter ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-extra-netfilter ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-usb ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-usb ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-wireless ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-modules-wireless ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-tools ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek-tools ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-core ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-core ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-devel ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-devel ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-core ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-core ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-deprecated ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-deprecated ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-desktop ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-desktop ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-extra ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-extra ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-extra-netfilter ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-extra-netfilter ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-usb ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-usb ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-wireless ol 10 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | kernel-uek64k-modules-wireless ol 9 | 0:6.12.0-205.92.4.2.el9uek | [ELSA-2026-500150](https://patchblox.com/security/data/fix/linux/elsa-2026-500150.md) | Aug 8, 2026 | | Linux | linux Debian 14 | 6.16.8-1 | [DEBIAN-CVE-2025-39874](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39874.md) | Sep 23, 2025 | --- Data as of 2026-11-08T13:06:02Z UTC. 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