{"id":"CVE-2026-89508","title":"RDMA/ucma: Lock the handler in ucma_set_ib_path()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/ucma: Lock the handler in ucma_set_ib_path()\n\nucma_set_ib_path() calls ucma_event_handler() straight from the write()\npath, without the handler lock that keeps ctx…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-367"],"vendor":"Linux","product":"Linux","affected":["Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < 3dd07b369371a2f29e1c3caf1ade85bb92b4c551","Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < b2da0d488a1c72956ebb0a57015ee8ee6a2f7748","Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < a7f8d26e653ee43b0b572984b8ec544d3b3b6f3c","Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < 71dc206f2e2a645dac78879768762451aa1799f7","Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < 764586f8f6180084c5a7d622120f526acc6ce0c9","Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < 28ac2dd416482d1c763c4af5d61af465b387fb50","Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < 43a7d8ae9f645dc00235cfa4bf57673c20b769f8","Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < ecbe7d36dc2de07e5dfbb4a8ff5b315ab43de820","Linux 5.10"],"published":"2026-09-11","updated":"2026-10-19","sourceUpdated":"2026-10-19T08:47:59.672Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89508","references":[{"url":"https://git.kernel.org/stable/c/3dd07b369371a2f29e1c3caf1ade85bb92b4c551"},{"url":"https://git.kernel.org/stable/c/b2da0d488a1c72956ebb0a57015ee8ee6a2f7748"},{"url":"https://git.kernel.org/stable/c/a7f8d26e653ee43b0b572984b8ec544d3b3b6f3c"},{"url":"https://git.kernel.org/stable/c/71dc206f2e2a645dac78879768762451aa1799f7"},{"url":"https://git.kernel.org/stable/c/764586f8f6180084c5a7d622120f526acc6ce0c9"},{"url":"https://git.kernel.org/stable/c/28ac2dd416482d1c763c4af5d61af465b387fb50"},{"url":"https://git.kernel.org/stable/c/43a7d8ae9f645dc00235cfa4bf57673c20b769f8"},{"url":"https://git.kernel.org/stable/c/ecbe7d36dc2de07e5dfbb4a8ff5b315ab43de820"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89508.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-89508"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2532308"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-89508"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89508"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89508.mbox"}],"tags":["cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00126,"epssPercentile":0.02234,"scores":{"cna":7.8,"vendor":5.5},"ingestedAt":"2026-09-14T15:23:07.452Z","slug":"CVE-2026-89508","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/ucma: Lock the handler in ucma_set_ib_path()\n\nucma_set_ib_path() calls ucma_event_handler() straight from the write()\npath, without the handler lock that keeps ctx->file stable while a uevent\nis queued.  The handler re-reads ctx->file for every dereference:\n\n\tmutex_lock(&ctx->file->mut);\t\t\t/* file A */\n\tlist_add_tail(&uevent->list, &ctx->file->event_list);\t/* file B */\n\tmutex_unlock(&ctx->file->mut);\t\t\t/* file B */\n\twake_up_interruptible(&ctx->file->poll_wait);\t/* file B */\n\nA concurrent ucma_migrate_id() reassigns ctx->file while the SET_OPTION\ncaller sleeps in mutex_lock(), so the list_add_tail() lands on file B's\nevent_list while only file A's mutex is held, racing every other user of\nthat list:\n\n  BUG: KASAN: slab-use-after-free in __list_add_valid_or_report+0x1aa/0x1c0\n  Read of size 8 at addr ffff888153c6a418 by task poc_corr/486\n  Call Trace:\n   __list_add_valid_or_report+0x1aa/0x1c0\n   ucma_event_handler+0x1be/0xc00\n   ucma_set_ib_path+0x45e/0x710\n   ucma_set_option+0x32e/0x590\n   ucma_write+0x1f9/0x330\n  Allocated by task 505:\n   ucma_write_cm_event+0x1a1/0x660\n  Freed by task 505:\n   kfree+0x1da/0x4c0\n   ucma_get_event+0x5d5/0x7e0\n\nThe freed object is a ucma_event that another thread dequeued from file B's\nlist under file B's mutex.  File A's mut is left held on top of that,\nwedging its next writer in uninterruptible sleep.\n\nThis path needs a bound and address-resolved cm_id, so it requires an RDMA\ndevice to be present.\n\nTake the handler lock around the call.\n\n## Affected\n\n- `Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < 3dd07b369371a2f29e1c3caf1ade85bb92b4c551`\n- `Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < b2da0d488a1c72956ebb0a57015ee8ee6a2f7748`\n- `Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < a7f8d26e653ee43b0b572984b8ec544d3b3b6f3c`\n- `Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < 71dc206f2e2a645dac78879768762451aa1799f7`\n- `Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < 764586f8f6180084c5a7d622120f526acc6ce0c9`\n- `Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < 28ac2dd416482d1c763c4af5d61af465b387fb50`\n- `Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < 43a7d8ae9f645dc00235cfa4bf57673c20b769f8`\n- `Linux >= 09e328e47a695b0d346598f5d6593ee598e64885 < ecbe7d36dc2de07e5dfbb4a8ff5b315ab43de820`\n- `Linux 5.10`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Moderate · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89508.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":224723,"id":"CVE-2026-89508","ts":1792401504255,"field":"cvss","old":"5.5","new":"7.8"},{"seq":224722,"id":"CVE-2026-89508","ts":1792401504255,"field":"severity","old":"medium","new":"high"},{"seq":206941,"id":"CVE-2026-89508","ts":1789749710176,"field":"cvss","old":"7.8","new":"5.5"},{"seq":206940,"id":"CVE-2026-89508","ts":1789749710176,"field":"severity","old":"high","new":"medium"},{"seq":197986,"id":"CVE-2026-89508","ts":1789384321263,"field":"cvss","old":"4.7","new":"7.8"},{"seq":197985,"id":"CVE-2026-89508","ts":1789384321263,"field":"severity","old":"medium","new":"high"},{"seq":183779,"id":"CVE-2026-89508","ts":1789356677353,"field":"cvss","old":"7.8","new":"4.7"},{"seq":183778,"id":"CVE-2026-89508","ts":1789356677353,"field":"severity","old":"high","new":"medium"},{"seq":153300,"id":"CVE-2026-89508","ts":1789285349945,"field":"cvss","old":null,"new":"7.8"},{"seq":153299,"id":"CVE-2026-89508","ts":1789285349945,"field":"severity","old":"none","new":"high"},{"seq":147402,"id":"CVE-2026-89508","ts":1789270210770,"field":"cvss","old":null,"new":"4.7"},{"seq":147401,"id":"CVE-2026-89508","ts":1789270210770,"field":"severity","old":"none","new":"medium"},{"seq":109162,"id":"CVE-2026-89508","ts":1789183730554,"field":"cvss","old":null,"new":"4.7"},{"seq":109161,"id":"CVE-2026-89508","ts":1789183730554,"field":"severity","old":"none","new":"medium"}]}