Bug 2546379 (CVE-2026-98200)
| Summary: | CVE-2026-98200 kernel: hwmon: (hp-wmi-sensors) Fix use-after-free in fungible_show() | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A flaw was found in the Linux kernel's HP WMI Sensors (hp-wmi-sensors) driver. Due to a missing lock when reading sensor properties, a race condition can occur when sensor data is freed and replaced during an update while another operation is reading it. A local user could exploit this flaw by concurrently accessing sensor files, triggering a use-after-free read that may cause a Denial of Service (DoS) or disclose sensitive kernel memory.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
In the Linux kernel, the following vulnerability has been resolved: hwmon: (hp-wmi-sensors) Fix use-after-free in fungible_show() nsensor->current_state is dynamically replaced as the sensor's state changes. update_numeric_sensor_from_wobj() does this by freeing the old string and installing a new one: if (strcmp(trimmed, nsensor->current_state)) { new_string = hp_wmi_strdup(dev, trimmed); if (new_string) { devm_kfree(dev, nsensor->current_state); nsensor->current_state = new_string; } } This function is only ever called from hp_wmi_update_info() while state->lock is held, so the free-and-replace itself is properly serialized against concurrent updates. fungible_show(), however, reads the same pointer after the lock has already been dropped: err = hp_wmi_update_info(state, info); if (err) return err; switch (prop) { ... case HP_WMI_PROPERTY_CURRENT_STATE: seq_printf(seqf, "%s\n", nsensor->current_state); break; hp_wmi_update_info() takes state->lock internally and releases it before returning, so by the time fungible_show() dereferences nsensor->current_state in seq_printf(), no lock is held. Two processes reading a sensor's current_state debugfs entry at overlapping times (or one reading it while another read of the same sensor triggers a refresh) can race: one thread's seq_printf() can be part-way through printing the string at the moment another thread's call into update_numeric_sensor_from_wobj() frees it with devm_kfree() and installs a new pointer, causing a use-after-free read. Take state->lock around the read in fungible_show() as well, so it can never run concurrently with the free-and-replace in update_numeric_sensor_from_wobj().