# CVE-2025-40249: linux: In the Linux kernel, the following vulnerability has been resolved: gpio: cdev: make sure the cdev fd is still activ... CVE-2025-40249 is fixed in 31 products on 1 platform, first by RHSA-2026:4012, released December 4, 2025. It is not reported as exploited. Patch Radar priority: High. - Web page: https://patchblox.com/security/cve/CVE-2025-40249 - Priority: High - CVSS: 7.8 (high) - EPSS: 0.0016 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: Dec 4, 2025 ## Description In the Linux kernel, the following vulnerability has been resolved: gpio: cdev: make sure the cdev fd is still active before emitting events With the final call to fput() on a file descriptor, the release action may be deferred and scheduled on a work queue. The reference count of that descriptor is still zero and it must not be used. It's possible that a GPIO change, we want to notify the user-space about, happens AFTER the reference count on the file descriptor associated with the character device went down to zero but BEFORE the .release() callback was called from the workqueue and so BEFORE we unregistered from the notifier. Using the regular get_file() routine in this situation triggers the following warning: struct file::f_count incremented from zero; use-after-free condition present! So use the get_file_active() variant that will return NULL on file descriptors that have been or are being released. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | kernel RHEL 10 | 6.12.0-124.43.1.el10_1 | [RHSA-2026:4012](https://patchblox.com/security/data/fix/linux/rhsa-2026-4012.md) | Dec 4, 2025 | | Linux | kernel ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-abi-stablelists almalinux 10 | 6.12.0-124.43.1.el10_1 | [ALSA-2026:4012](https://patchblox.com/security/data/fix/linux/alsa-2026-4012.md) | Mar 9, 2026 | | Linux | kernel-abi-stablelists ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-core ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-cross-headers ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-debug ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-debug-core ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-debug-devel ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-debug-devel-matched ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-debug-modules ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-debug-modules-core ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-debug-modules-extra ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-debug-uki-virt ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-devel ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-devel-matched ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-doc almalinux 10 | 6.12.0-124.43.1.el10_1 | [ALSA-2026:4012](https://patchblox.com/security/data/fix/linux/alsa-2026-4012.md) | Mar 9, 2026 | | Linux | kernel-doc ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-headers ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-modules ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-modules-core ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-modules-extra ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-modules-extra-matched ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-tools ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-tools-libs ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-tools-libs-devel ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-uki-virt ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | kernel-uki-virt-addons ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | libperf ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | linux Debian 14 | 6.17.10-1 | [DEBIAN-CVE-2025-40249](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40249.md) | Dec 4, 2025 | | Linux | perf ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | python3-perf ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | rtla ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | | Linux | rv ol 10 | 0:6.12.0-124.43.1.el10_1 | [ELSA-2026-4012](https://patchblox.com/security/data/fix/linux/elsa-2026-4012.md) | Mar 10, 2026 | --- Data as of 2026-11-08T00:53:09Z UTC. 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