{"cve":"CVE-2024-26687","nvd":{"published":"2024-04-03T15:15:52.313","modified":"2026-06-17T07:18:05.860","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nxen/events: close evtchn after mapping cleanup\n\nshutdown_pirq and startup_pirq are not taking the\nirq_mapping_update_lock because they can't due to lock inversion. Both\nare called with the irq_desc->lock being taking. The lock order,\nhowever, is first irq_mapping_update_lock and then irq_desc->lock.\n\nThis opens multiple races:\n- shutdown_pirq can be interrupted by a function that allocates an event\n  channel:\n\n  CPU0                        CPU1\n  shutdown_pirq {\n    xen_evtchn_close(e)\n                              __startup_pirq {\n                                EVTCHNOP_bind_pirq\n                                  -> returns just freed evtchn e\n                                set_evtchn_to_irq(e, irq)\n                              }\n    xen_irq_info_cleanup() {\n      set_evtchn_to_irq(e, -1)\n    }\n  }\n\n  Assume here event channel e refers here to the same event channel\n  number.\n  After this race the evtchn_to_irq mapping for e is invalid (-1).\n\n- __startup_pirq races with __unbind_from_irq in a similar way. Because\n  __startup_pirq doesn't take irq_mapping_update_lock it can grab the\n  evtchn that __unbind_from_irq is currently freeing and cleaning up. In\n  this case even though the event channel is allocated, its mapping can\n  be unset in evtchn_to_irq.\n\nThe fix is to first cleanup the mappings and then close the event\nchannel. In this way, when an event channel gets allocated it's\npotential previous evtchn_to_irq mappings are guaranteed to be unset already.\nThis is also the reverse order of the allocation where first the event\nchannel is allocated and then the mappings are setup.\n\nOn a 5.10 kernel prior to commit 3fcdaf3d7634 (\"xen/events: modify internal\n[un]bind interfaces\"), we hit a BUG like the following during probing of NVMe\ndevices. The issue is that during nvme_setup_io_queues, pci_free_irq\nis called for every device which results in a call to shutdown_pirq.\nWith many nvme devices it's therefore likely to hit this race during\nboot because there will be multiple calls to shutdown_pirq and\nstartup_pirq are running potentially in parallel.\n\n  ------------[ cut here ]------------\n  blkfront: xvda: barrier or flush: disabled; persistent grants: enabled; indirect descriptors: enabled; bounce buffer: enabled\n  kernel BUG at drivers/xen/events/events_base.c:499!\n  invalid opcode: 0000 [#1] SMP PTI\n  CPU: 44 PID: 375 Comm: kworker/u257:23 Not tainted 5.10.201-191.748.amzn2.x86_64 #1\n  Hardware name: Xen HVM domU, BIOS 4.11.amazon 08/24/2006\n  Workqueue: nvme-reset-wq nvme_reset_work\n  RIP: 0010:bind_evtchn_to_cpu+0xdf/0xf0\n  Code: 5d 41 5e c3 cc cc cc cc 44 89 f7 e8 2b 55 ad ff 49 89 c5 48 85 c0 0f 84 64 ff ff ff 4c 8b 68 30 41 83 fe ff 0f 85 60 ff ff ff <0f> 0b 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 0f 1f 44 00 00\n  RSP: 0000:ffffc9000d533b08 EFLAGS: 00010046\n  RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000006\n  RDX: 0000000000000028 RSI: 00000000ffffffff RDI: 00000000ffffffff\n  RBP: ffff888107419680 R08: 0000000000000000 R09: ffffffff82d72b00\n  R10: 0000000000000000 R11: 0000000000000000 R12: 00000000000001ed\n  R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000002\n  FS:  0000000000000000(0000) GS:ffff88bc8b500000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 0000000000000000 CR3: 0000000002610001 CR4: 00000000001706e0\n  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  Call Trace:\n   ? show_trace_log_lvl+0x1c1/0x2d9\n   ? show_trace_log_lvl+0x1c1/0x2d9\n   ? set_affinity_irq+0xdc/0x1c0\n   ? __die_body.cold+0x8/0xd\n   ? die+0x2b/0x50\n   ? do_trap+0x90/0x110\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? do_error_trap+0x65/0x80\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? exc_invalid_op+0x4e/0x70\n   ? bind_evtchn_to_cpu+0xdf/0xf0\n   ? asm_exc_invalid_op+0x12/0x20\n   ? bind_evtchn_to_cpu+0xdf/0x\n---truncated---","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-459"],"references":["https://git.kernel.org/stable/c/0fc88aeb2e32b76db3fe6a624b8333dbe621b8fd","https://git.kernel.org/stable/c/20980195ec8d2e41653800c45c8c367fa1b1f2b4","https://git.kernel.org/stable/c/585a344af6bcac222608a158fc2830ff02712af5","https://git.kernel.org/stable/c/9470f5b2503cae994098dea9682aee15b313fa44","https://git.kernel.org/stable/c/9be71aa12afa91dfe457b3fb4a444c42b1ee036b"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:47:51.568503435+00:00"},"epss":{"cve":"CVE-2024-26687","score":0.00228,"percentile":0.13685,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}