{"id":"CVE-2026-45910","state":"PUBLISHED","title":"RDMA/rxe: Fix race condition in QP timer handlers","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Fix race condition in QP timer handlers\n\nI encontered the following warning:\n WARNING: drivers/infiniband/sw/rxe/rxe_task.c:249 at rxe_sched_task+0x1c8/0x238 [rdma_rxe], CPU#0: swapper/0/0\n...\n  libsha1 [last unloaded: ip6_udp_tunnel]\n CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G         C          6.19.0-rc5-64k-v8+ #37 PREEMPT\n Tainted: [C]=CRAP\n Hardware name: Raspberry Pi 4 Model B Rev 1.2\n Call trace:\n  rxe_sched_task+0x1c8/0x238 [rdma_rxe] (P)\n  retransmit_timer+0x130/0x188 [rdma_rxe]\n  call_timer_fn+0x68/0x4d0\n  __run_timers+0x630/0x888\n...\n WARNING: drivers/infiniband/sw/rxe/rxe_task.c:38 at rxe_sched_task+0x1c0/0x238 [rdma_rxe], CPU#0: swapper/0/0\n...\n WARNING: drivers/infiniband/sw/rxe/rxe_task.c:111 at do_work+0x488/0x5c8 [rdma_rxe], CPU#3: kworker/u17:4/93400\n...\n refcount_t: underflow; use-after-free.\n WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x138/0x1a0, CPU#3: kworker/u17:4/93400\n\nThe issue is caused by a race condition between retransmit_timer() and\nrxe_destroy_qp, leading to the Queue Pair's (QP) reference count dropping\nto zero during timer handler execution.\n\nIt seems this warning is harmless because rxe_qp_do_cleanup() will flush\nall pending timers and requests.\n\nExample of flow causing the issue:\n\nCPU0                                   CPU1\nretransmit_timer() {\n    spin_lock_irqsave\n                           rxe_destroy_qp()\n                            __rxe_cleanup()\n                              __rxe_put() // qp->ref_count decrease to 0\n                            rxe_qp_do_cleanup() {\n    if (qp->valid) {\n        rxe_sched_task() {\n            WARN_ON(rxe_read(task->qp) <= 0);\n        }\n    }\n    spin_unlock_irqrestore\n}\n                              spin_lock_irqsave\n                              qp->valid = 0\n                              spin_unlock_irqrestore\n                            }\n\nEnsure the QP's reference count is maintained and its validity is checked\nwithin the timer callbacks by adding calls to rxe_get(qp) and corresponding\nrxe_put(qp) after use.","publishedAt":"2026-05-27T12:17:24.619Z","updatedAt":"2026-10-19T19:26:39.625Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d94671632572813e90bcf475bb4c7d51fbf20173","status":"affected","lessThan":"756c93d6df7c3bc599f6590b8e5afead6a41de1c","versionType":"git"},{"version":"d94671632572813e90bcf475bb4c7d51fbf20173","status":"affected","lessThan":"3c2ae79fb19dfd67341c14f1e78a5f1744eacfe2","versionType":"git"},{"version":"d94671632572813e90bcf475bb4c7d51fbf20173","status":"affected","lessThan":"5ae9da022ee3c97e6469eabcddce9271501ddbad","versionType":"git"},{"version":"d94671632572813e90bcf475bb4c7d51fbf20173","status":"affected","lessThan":"da379ca16af3722f159860d91a99cb6976a7500f","versionType":"git"},{"version":"d94671632572813e90bcf475bb4c7d51fbf20173","status":"affected","lessThan":"87bf646921430e303176edc4eb07c30160361b73","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/rxe/rxe_comp.c","drivers/infiniband/sw/rxe/rxe_req.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.4","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.4","versionType":"semver"},{"version":"6.6.128","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.75","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.14","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.4","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/rxe/rxe_comp.c","drivers/infiniband/sw/rxe/rxe_req.c"]}],"references":["https://git.kernel.org/stable/c/756c93d6df7c3bc599f6590b8e5afead6a41de1c","https://git.kernel.org/stable/c/3c2ae79fb19dfd67341c14f1e78a5f1744eacfe2","https://git.kernel.org/stable/c/5ae9da022ee3c97e6469eabcddce9271501ddbad","https://git.kernel.org/stable/c/da379ca16af3722f159860d91a99cb6976a7500f","https://git.kernel.org/stable/c/87bf646921430e303176edc4eb07c30160361b73"],"weaknesses":["CWE-362"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/45xxx/CVE-2026-45910.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-45910","state":"PUBLISHED","datePublished":"2026-05-27T12:17:24.619Z","dateUpdated":"2026-10-19T19:26:39.625Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-13T15:03:33.084Z"},"containers":{"cna":{"title":"RDMA/rxe: Fix race condition in QP timer handlers","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Fix race condition in QP timer handlers\n\nI encontered the following warning:\n WARNING: drivers/infiniband/sw/rxe/rxe_task.c:249 at rxe_sched_task+0x1c8/0x238 [rdma_rxe], CPU#0: swapper/0/0\n...\n  libsha1 [last unloaded: ip6_udp_tunnel]\n CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G         C          6.19.0-rc5-64k-v8+ #37 PREEMPT\n Tainted: [C]=CRAP\n Hardware name: Raspberry Pi 4 Model B Rev 1.2\n Call trace:\n  rxe_sched_task+0x1c8/0x238 [rdma_rxe] (P)\n  retransmit_timer+0x130/0x188 [rdma_rxe]\n  call_timer_fn+0x68/0x4d0\n  __run_timers+0x630/0x888\n...\n WARNING: drivers/infiniband/sw/rxe/rxe_task.c:38 at rxe_sched_task+0x1c0/0x238 [rdma_rxe], CPU#0: swapper/0/0\n...\n WARNING: drivers/infiniband/sw/rxe/rxe_task.c:111 at do_work+0x488/0x5c8 [rdma_rxe], CPU#3: kworker/u17:4/93400\n...\n refcount_t: underflow; use-after-free.\n WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x138/0x1a0, CPU#3: kworker/u17:4/93400\n\nThe issue is caused by a race condition between retransmit_timer() and\nrxe_destroy_qp, leading to the Queue Pair's (QP) reference count dropping\nto zero during timer handler execution.\n\nIt seems this warning is harmless because rxe_qp_do_cleanup() will flush\nall pending timers and requests.\n\nExample of flow causing the issue:\n\nCPU0                                   CPU1\nretransmit_timer() {\n    spin_lock_irqsave\n                           rxe_destroy_qp()\n                            __rxe_cleanup()\n                              __rxe_put() // qp->ref_count decrease to 0\n                            rxe_qp_do_cleanup() {\n    if (qp->valid) {\n        rxe_sched_task() {\n            WARN_ON(rxe_read(task->qp) <= 0);\n        }\n    }\n    spin_unlock_irqrestore\n}\n                              spin_lock_irqsave\n                              qp->valid = 0\n                              spin_unlock_irqrestore\n                            }\n\nEnsure the QP's reference count is maintained and its validity is checked\nwithin the timer callbacks by adding calls to rxe_get(qp) and corresponding\nrxe_put(qp) after use."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d94671632572813e90bcf475bb4c7d51fbf20173","status":"affected","lessThan":"756c93d6df7c3bc599f6590b8e5afead6a41de1c","versionType":"git"},{"version":"d94671632572813e90bcf475bb4c7d51fbf20173","status":"affected","lessThan":"3c2ae79fb19dfd67341c14f1e78a5f1744eacfe2","versionType":"git"},{"version":"d94671632572813e90bcf475bb4c7d51fbf20173","status":"affected","lessThan":"5ae9da022ee3c97e6469eabcddce9271501ddbad","versionType":"git"},{"version":"d94671632572813e90bcf475bb4c7d51fbf20173","status":"affected","lessThan":"da379ca16af3722f159860d91a99cb6976a7500f","versionType":"git"},{"version":"d94671632572813e90bcf475bb4c7d51fbf20173","status":"affected","lessThan":"87bf646921430e303176edc4eb07c30160361b73","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/rxe/rxe_comp.c","drivers/infiniband/sw/rxe/rxe_req.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.4","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.4","versionType":"semver"},{"version":"6.6.128","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.75","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.14","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.4","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/sw/rxe/rxe_comp.c","drivers/infiniband/sw/rxe/rxe_req.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/756c93d6df7c3bc599f6590b8e5afead6a41de1c"},{"url":"https://git.kernel.org/stable/c/3c2ae79fb19dfd67341c14f1e78a5f1744eacfe2"},{"url":"https://git.kernel.org/stable/c/5ae9da022ee3c97e6469eabcddce9271501ddbad"},{"url":"https://git.kernel.org/stable/c/da379ca16af3722f159860d91a99cb6976a7500f"},{"url":"https://git.kernel.org/stable/c/87bf646921430e303176edc4eb07c30160361b73"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The race is between the local rxe_destroy_qp verb and a local QP timer firing, both driven through the RDMA uverbs interface; a remote peer cannot create or destroy QPs, so local access is required.\nAC:L - This is a race the attacker controls on both sides — creating a QP, driving RC traffic to arm the retransmit/rnr_nak timers, then destroying the QP — and it can be retried indefinitely across many QPs.\nPR:L - Triggering requires issuing RDMA verbs (create/destroy QP, post sends) via the uverbs device, which in RDMA deployments is routinely granted to non-root users (rdma group / container device access).\nUI:N - The attacker performs all QP creation, traffic, and destruction operations themselves with no victim action required.\nS:U - The use-after-free is contained within the kernel's own security authority with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The refcount underflow / use-after-free on the QP object can give an attacker control over freed-object contents, enabling kernel memory disclosure.\nI:H - A use-after-free of the QP object enables heap grooming and arbitrary write primitives, per kernel UAF scoring guidance.\nA:H - The refcount underflow/use-after-free produces kernel warnings and can crash or panic the system when the freed QP is accessed."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:28:43.189Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.6.128"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.12.75"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.18.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"6.19.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.4","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-45910","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:18:23.890449Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-362","lang":"en","type":"CWE","description":"CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:26:39.625Z"}}]}}}