{"id":"CVE-2026-45856","state":"PUBLISHED","title":"RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send\n\nib_uverbs_post_send() uses cmd.wqe_size from userspace without any\nvalidation before passing it to kmalloc() and using the allocated\nbuffer as struct ib_uverbs_send_wr.\n\nIf a user provides a small wqe_size value (e.g., 1), kmalloc() will\nsucceed, but subsequent accesses to user_wr->opcode, user_wr->num_sge,\nand other fields will read beyond the allocated buffer, resulting in\nan out-of-bounds read from kernel heap memory. This could potentially\nleak sensitive kernel information to userspace.\n\nAdditionally, providing an excessively large wqe_size can trigger a\nWARNING in the memory allocation path, as reported by syzkaller.\n\nThis is inconsistent with ib_uverbs_unmarshall_recv() which properly\nvalidates that wqe_size >= sizeof(struct ib_uverbs_recv_wr) before\nproceeding.\n\nAdd the same validation for ib_uverbs_post_send() to ensure wqe_size\nis at least sizeof(struct ib_uverbs_send_wr).","publishedAt":"2026-05-27T12:15:33.209Z","updatedAt":"2026-10-19T19:26:38.460Z","severity":{"score":7.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"9b5ac1c15334d46c0dbd49d64a2257b929500163","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"01c9b152647dc70dc06a4a2eff86ebb3b3c76075","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"bf1feed1a7886af945f92890493aefd2b5c9928a","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"d533425ac1f2925b4fc3e4ed9b9d72362cb23475","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"bf4454da8b1e712714628c0a0d6e7845bb40790a","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"bef70ff9841990658610512b4a18e4a88c9b4df6","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/core/uverbs_cmd.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.0","versionType":"semver"},{"version":"5.10.252","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.202","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.165","status":"unaffected","lessThanOrEqual":"6.1.*","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/core/uverbs_cmd.c"]}],"references":["https://git.kernel.org/stable/c/9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7","https://git.kernel.org/stable/c/9b5ac1c15334d46c0dbd49d64a2257b929500163","https://git.kernel.org/stable/c/01c9b152647dc70dc06a4a2eff86ebb3b3c76075","https://git.kernel.org/stable/c/bf1feed1a7886af945f92890493aefd2b5c9928a","https://git.kernel.org/stable/c/d533425ac1f2925b4fc3e4ed9b9d72362cb23475","https://git.kernel.org/stable/c/bf4454da8b1e712714628c0a0d6e7845bb40790a","https://git.kernel.org/stable/c/bef70ff9841990658610512b4a18e4a88c9b4df6","https://git.kernel.org/stable/c/1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/45xxx/CVE-2026-45856.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-45856","state":"PUBLISHED","datePublished":"2026-05-27T12:15:33.209Z","dateUpdated":"2026-10-19T19:26:38.460Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-13T15:03:33.079Z"},"containers":{"cna":{"title":"RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send\n\nib_uverbs_post_send() uses cmd.wqe_size from userspace without any\nvalidation before passing it to kmalloc() and using the allocated\nbuffer as struct ib_uverbs_send_wr.\n\nIf a user provides a small wqe_size value (e.g., 1), kmalloc() will\nsucceed, but subsequent accesses to user_wr->opcode, user_wr->num_sge,\nand other fields will read beyond the allocated buffer, resulting in\nan out-of-bounds read from kernel heap memory. This could potentially\nleak sensitive kernel information to userspace.\n\nAdditionally, providing an excessively large wqe_size can trigger a\nWARNING in the memory allocation path, as reported by syzkaller.\n\nThis is inconsistent with ib_uverbs_unmarshall_recv() which properly\nvalidates that wqe_size >= sizeof(struct ib_uverbs_recv_wr) before\nproceeding.\n\nAdd the same validation for ib_uverbs_post_send() to ensure wqe_size\nis at least sizeof(struct ib_uverbs_send_wr)."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"9b5ac1c15334d46c0dbd49d64a2257b929500163","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"01c9b152647dc70dc06a4a2eff86ebb3b3c76075","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"bf1feed1a7886af945f92890493aefd2b5c9928a","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"d533425ac1f2925b4fc3e4ed9b9d72362cb23475","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"bf4454da8b1e712714628c0a0d6e7845bb40790a","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"bef70ff9841990658610512b4a18e4a88c9b4df6","versionType":"git"},{"version":"c3bea3d2dc5358e05541527283279102383b0231","status":"affected","lessThan":"1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/core/uverbs_cmd.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.0","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.0","versionType":"semver"},{"version":"5.10.252","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.202","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.165","status":"unaffected","lessThanOrEqual":"6.1.*","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/core/uverbs_cmd.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7"},{"url":"https://git.kernel.org/stable/c/9b5ac1c15334d46c0dbd49d64a2257b929500163"},{"url":"https://git.kernel.org/stable/c/01c9b152647dc70dc06a4a2eff86ebb3b3c76075"},{"url":"https://git.kernel.org/stable/c/bf1feed1a7886af945f92890493aefd2b5c9928a"},{"url":"https://git.kernel.org/stable/c/d533425ac1f2925b4fc3e4ed9b9d72362cb23475"},{"url":"https://git.kernel.org/stable/c/bf4454da8b1e712714628c0a0d6e7845bb40790a"},{"url":"https://git.kernel.org/stable/c/bef70ff9841990658610512b4a18e4a88c9b4df6"},{"url":"https://git.kernel.org/stable/c/1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable code is reached via write() on the local RDMA uverbs character device (/dev/infiniband/uverbs*) dispatched through UAPI_DEF_WRITE_IO; it is not reachable over any network.\nAC:L - The attacker fully controls cmd.wqe_size and can reliably trigger the OOB read by simply setting wqe_size=1 (or the WARN with a huge value); no uncontrolled conditions are involved.\nPR:L - An unprivileged local user with access to the RDMA uverbs device (the normal case on RDMA-enabled systems, and obtainable via Soft-RoCE) can open a context, create a QP, and issue POST_SEND; no real-root privilege is required.\nUI:N - The command is issued directly by the attacker via a syscall; no action by any other user is needed.\nS:U - The OOB read and resulting impact remain within the kernel's own security authority; no crossing of a security boundary (VM/IOMMU/sandbox) occurs.\nC:H - The bug reads ~48 bytes of kernel heap memory beyond the undersized allocation, and the leaked values (e.g. wr_id) are returned to userspace via completion polling, giving a repeatable kernel-heap information disclosure.\nI:N - The defect is purely an out-of-bounds read; num_sge is bounded by the sge_count check, so no kernel memory is modified and there is no write primitive.\nA:H - An excessively large wqe_size triggers a WARNING in the allocator (syzkaller-reported), which becomes a kernel panic under the common panic_on_warn hardening, causing denial of service."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:28:29.851Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"5.10.252"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"5.15.202"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.1.165"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.6.128"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.12.75"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.18.14"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"6.19.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.0","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-45856","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T15:18:02.441726Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","type":"CWE","description":"CWE-125 Out-of-bounds Read"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:26:38.460Z"}}]}}}