Spurious GPIO events via notifier teardown race
Published May 30, 2024 · Updated May 12, 2026
Use-after-free in Linux GPIO character devices allows local users to generate a spurious line event during concurrent device teardown. gpio_chrdev_release frees watched_lines before lineinfo_changed_nb finishes unregistering, so lineinfo_changed_notify can call test_bit on the freed bitmap. The race requires a device close to overlap a GPIO line release; Siemens also identifies its SIMATIC S7-1500 TM MFP GNU/Linux subsystem as affected, while userspace cannot read the resulting event after the close.
Summary
What happened
Use-after-free in Linux GPIO character devices allows local users to generate a spurious line event during concurrent device teardown. gpio_chrdev_release frees watched_lines before lineinfo_changed_nb finishes unregistering, so lineinfo_changed_notify can call test_bit on the freed bitmap. The race requires a device close to overlap a GPIO line release; Siemens also identifies its SIMATIC S7-1500 TM MFP GNU/Linux subsystem as affected, while userspace cannot read the resulting event after the close.
The record
- CVE
- CVE-2024-36899
- Published
- May 30, 2024
- Updated
- May 12, 2026
- Vendor
- Siemens
- Product
- SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
- Classifications
- CWE-362, CWE-416
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 30, 2024CVE publishedPublication date reported by the CVE source.
- May 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
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- Affected versionversion=0 <*
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