CVE-2026-89508

CVE CVE-2026-89508EUVD EUVD-2026-76414Published 2026-09-11T19:43:54.000ZLast changed 2026-09-14T12:00:35.000ZCVSS 7.8

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: RDMA/ucma: Lock the handler in ucma_set_ib_path() ucma_set_ib_path() calls ucma_event_handler() straight from the write() path, without the handler lock that keeps ctx->file stable while a uevent is queued. The handler re-reads ctx->file for every dereference: mutex_lock(&ctx->file->mut); /* file A */ list_add_tail(&uevent->list, &ctx->file->event_list); /* file B */ mutex_unlock(&ctx->file->mut); /* file B */ wake_up_interruptible(&ctx->file->poll_wait); /* file B */ A concurrent ucma_migrate_id() reassigns ctx->file while the SET_OPTION caller sleeps in mutex_lock(), so the list_add_tail() lands on file B's event_list while only file A's mutex is held, racing every other user of that list: BUG: KASAN: slab-use-after-free in __list_add_valid_or_report+0x1aa/0x1c0 Read of size 8 at addr ffff888153c6a418 by task poc_corr/486 Call Trace: __list_add_valid_or_report+0x1aa/0x1c0 ucma_event_handler+0x1be/0xc00 ucma_set_ib_path+0x45e/0x710 ucma_set_option+0x32e/0x590 ucma_write+0x1f9/0x330 Allocated by task 505: ucma_write_cm_event+0x1a1/0x660 Freed by task 505: kfree+0x1da/0x4c0 ucma_get_event+0x5d5/0x7e0 The freed object is a ucma_event that another thread dequeued from file B's list under file B's mutex. File A's mut is left held on top of that, wedging its next writer in uninterruptible sleep. This path needs a bound and address-resolved cm_id, so it requires an RDMA device to be present. Take the handler lock around the call.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux 09e328e47a695b0d346598f5d6593ee598e64885 <a7f8d26e653ee43b0b572984b8ec544d3b3b6f3c; patch: 5.10.270; 09e328e47a695b0d346598f5d6593ee598e64885 <b2da0d488a1c72956ebb0a57015ee8ee6a2f7748; patch: 5.15.221; patch: 6.6.157; patch: 7.2.4; 09e328e47a695b0d346598f5d6593ee598e64885 <71dc206f2e2a645dac78879768762451aa1799f7; 09e328e47a695b0d346598f5d6593ee598e64885 <764586f8f6180084c5a7d622120f526acc6ce0c9; patch: 0; 09e328e47a695b0d346598f5d6593ee598e64885 <28ac2dd416482d1c763c4af5d61af465b387fb50; patch: 6.12.109; 09e328e47a695b0d346598f5d6593ee598e64885 <3dd07b369371a2f29e1c3caf1ade85bb92b4c551; patch: 6.1.188; 09e328e47a695b0d346598f5d6593ee598e64885 <43a7d8ae9f645dc00235cfa4bf57673c20b769f8; patch: 7.3-rc1; 5.10; 09e328e47a695b0d346598f5d6593ee598e64885 <ecbe7d36dc2de07e5dfbb4a8ff5b315ab43de820; patch: 6.18.50

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

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