{"id":"AZL-64707","summary":"CVE-2025-38217 affecting package kernel for versions less than 6.6.96.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nhwmon: (ftsteutates) Fix TOCTOU race in fts_read()\n\nIn the fts_read() function, when handling hwmon_pwm_auto_channels_temp,\nthe code accesses the shared variable data-\u003efan_source[channel] twice\nwithout holding any locks. It is first checked against\nFTS_FAN_SOURCE_INVALID, and if the check passes, it is read again\nwhen used as an argument to the BIT() macro.\n\nThis creates a Time-of-Check to Time-of-Use (TOCTOU) race condition.\nAnother thread executing fts_update_device() can modify the value of\ndata-\u003efan_source[channel] between the check and its use. If the value\nis changed to FTS_FAN_SOURCE_INVALID (0xff) during this window, the\nBIT() macro will be called with a large shift value (BIT(255)).\nA bit shift by a value greater than or equal to the type width is\nundefined behavior and can lead to a crash or incorrect values being\nreturned to userspace.\n\nFix this by reading data-\u003efan_source[channel] into a local variable\nonce, eliminating the race condition. Additionally, add a bounds check\nto ensure the value is less than BITS_PER_LONG before passing it to\nthe BIT() macro, making the code more robust against undefined behavior.\n\nThis possible bug was found by an experimental static analysis tool\ndeveloped by our team.","modified":"2026-04-01T05:20:50.323505Z","published":"2025-07-04T14:15:30Z","upstream":["CVE-2025-38217"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-38217"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.96.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-64707.json"}}],"schema_version":"1.7.5"}