{"id":"CVE-2025-38632","title":"pinmux: fix race causing mux_owner NULL with active mux_usecount","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\npinmux: fix race causing mux_owner NULL with active mux_usecount\n\ncommit 5a3e85c3c397 (\"pinmux: Use sequential access to access\ndesc->pinmux data\") tried to address the…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= d25e45dcf8e32062f7935e4ba154869043812ab6 < 8434dec94e73cad527341d6280895191d949a702","Linux >= 2da32aed4a97ca1d70fb8b77926f72f30ce5fb4b < 9b2a3e7189028aa7c4d53a84364f2ea9fb209787","Linux >= c11e2ec9a780f54982a187ee10ffd1b810715c85 < 9ea3f6b9a67be3476e331ce51cac316c2614a564","Linux >= 5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e < b7bd6e3971eb7f0e34d2fdce1b18b08094e0c804","Linux >= 5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e < 22b585cbd67d14df3b91529d1b990661c300faa9","Linux >= 5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e < 0b075c011032f88d1cfde3b45d6dcf08b44140eb","Linux >= 6.6.66 < 6.6.102","Linux >= 6.12.5 < 6.12.42","Linux 6.13"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-05T21:05:29.790577Z"},"published":"2025-08-22","updated":"2026-11-05","sourceUpdated":"2026-11-05T21:12:49.802Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-38632","references":[{"url":"https://git.kernel.org/stable/c/8434dec94e73cad527341d6280895191d949a702"},{"url":"https://git.kernel.org/stable/c/9b2a3e7189028aa7c4d53a84364f2ea9fb209787"},{"url":"https://git.kernel.org/stable/c/9ea3f6b9a67be3476e331ce51cac316c2614a564"},{"url":"https://git.kernel.org/stable/c/b7bd6e3971eb7f0e34d2fdce1b18b08094e0c804"},{"url":"https://git.kernel.org/stable/c/22b585cbd67d14df3b91529d1b990661c300faa9"},{"url":"https://git.kernel.org/stable/c/0b075c011032f88d1cfde3b45d6dcf08b44140eb"}],"tags":["cve.org"],"epss":0.00142,"epssPercentile":0.03549,"ingestedAt":"2026-11-03T19:53:18.505Z","slug":"CVE-2025-38632","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\npinmux: fix race causing mux_owner NULL with active mux_usecount\n\ncommit 5a3e85c3c397 (\"pinmux: Use sequential access to access\ndesc->pinmux data\") tried to address the issue when two client of the\nsame gpio calls pinctrl_select_state() for the same functionality, was\nresulting in NULL pointer issue while accessing desc->mux_owner.\nHowever, issue was not completely fixed due to the way it was handled\nand it can still result in the same NULL pointer.\n\nThe issue occurs due to the following interleaving:\n\n     cpu0 (process A)                   cpu1 (process B)\n\n      pin_request() {                   pin_free() {\n\n                                         mutex_lock()\n                                         desc->mux_usecount--; //becomes 0\n                                         ..\n                                         mutex_unlock()\n\n  mutex_lock(desc->mux)\n  desc->mux_usecount++; // becomes 1\n  desc->mux_owner = owner;\n  mutex_unlock(desc->mux)\n\n                                         mutex_lock(desc->mux)\n                                         desc->mux_owner = NULL;\n                                         mutex_unlock(desc->mux)\n\nThis sequence leads to a state where the pin appears to be in use\n(`mux_usecount == 1`) but has no owner (`mux_owner == NULL`), which can\ncause NULL pointer on next pin_request on the same pin.\n\nEnsure that updates to mux_usecount and mux_owner are performed\natomically under the same lock. Only clear mux_owner when mux_usecount\nreaches zero and no new owner has been assigned.\n\n## Affected\n\n- `Linux >= d25e45dcf8e32062f7935e4ba154869043812ab6 < 8434dec94e73cad527341d6280895191d949a702`\n- `Linux >= 2da32aed4a97ca1d70fb8b77926f72f30ce5fb4b < 9b2a3e7189028aa7c4d53a84364f2ea9fb209787`\n- `Linux >= c11e2ec9a780f54982a187ee10ffd1b810715c85 < 9ea3f6b9a67be3476e331ce51cac316c2614a564`\n- `Linux >= 5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e < b7bd6e3971eb7f0e34d2fdce1b18b08094e0c804`\n- `Linux >= 5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e < 22b585cbd67d14df3b91529d1b990661c300faa9`\n- `Linux >= 5a3e85c3c397c781393ea5fb2f45b1f60f8a4e6e < 0b075c011032f88d1cfde3b45d6dcf08b44140eb`\n- `Linux >= 6.6.66 < 6.6.102`\n- `Linux >= 6.12.5 < 6.12.42`\n- `Linux 6.13`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}