{"cve":"CVE-2024-36899","nvd":{"published":"2024-05-30T16:15:13.510","modified":"2026-10-15T01:18:23.673","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ngpiolib: cdev: Fix use after free in lineinfo_changed_notify\n\nThe use-after-free issue occurs as follows: when the GPIO chip device file\nis being closed by invoking gpio_chrdev_release(), watched_lines is freed\nby bitmap_free(), but the unregistration of lineinfo_changed_nb notifier\nchain failed due to waiting write rwsem. Additionally, one of the GPIO\nchip's lines is also in the release process and holds the notifier chain's\nread rwsem. Consequently, a race condition leads to the use-after-free of\nwatched_lines.\n\nHere is the typical stack when issue happened:\n\n[free]\ngpio_chrdev_release()\n  --> bitmap_free(cdev->watched_lines)                  <-- freed\n  --> blocking_notifier_chain_unregister()\n    --> down_write(&nh->rwsem)                          <-- waiting rwsem\n          --> __down_write_common()\n            --> rwsem_down_write_slowpath()\n                  --> schedule_preempt_disabled()\n                    --> schedule()\n\n[use]\nst54spi_gpio_dev_release()\n  --> gpio_free()\n    --> gpiod_free()\n      --> gpiod_free_commit()\n        --> gpiod_line_state_notify()\n          --> blocking_notifier_call_chain()\n            --> down_read(&nh->rwsem);                  <-- held rwsem\n            --> notifier_call_chain()\n              --> lineinfo_changed_notify()\n                --> test_bit(xxxx, cdev->watched_lines) <-- use after free\n\nThe side effect of the use-after-free issue is that a GPIO line event is\nbeing generated for userspace where it shouldn't. However, since the chrdev\nis being closed, userspace won't have the chance to read that event anyway.\n\nTo fix the issue, call the bitmap_free() function after the unregistration\nof lineinfo_changed_nb notifier chain.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.0},"cwes":["CWE-362","CWE-416"],"references":["https://git.kernel.org/stable/c/02f6b0e1ec7e0e7d059dddc893645816552039da","https://git.kernel.org/stable/c/2d008d4961b039d2edce8976289773961b7e5fb5","https://git.kernel.org/stable/c/2dfbb920a89bdc58087672ad5325dc6c588b6860","https://git.kernel.org/stable/c/95ca7c90eaf5ea8a8460536535101e3e81160e2a","https://git.kernel.org/stable/c/ca710b5f40b8b16fdcad50bebd47f50e4c62d239"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:51:20.603330631+00:00"},"epss":{"cve":"CVE-2024-36899","score":0.00178,"percentile":0.07266,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}