RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send_CVE-2026-45856

{
    "lastseen": "",
    "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).",
    "published": "2026-05-27T12:15:33.209Z",
    "modified": "2026-05-30T10:45:33.505Z",
    "type": "cve",
    "title": "RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7\nhttps://git.kernel.org/stable/c/9b5ac1c15334d46c0dbd49d64a2257b929500163\nhttps://git.kernel.org/stable/c/01c9b152647dc70dc06a4a2eff86ebb3b3c76075\nhttps://git.kernel.org/stable/c/bf1feed1a7886af945f92890493aefd2b5c9928a\nhttps://git.kernel.org/stable/c/d533425ac1f2925b4fc3e4ed9b9d72362cb23475\nhttps://git.kernel.org/stable/c/bf4454da8b1e712714628c0a0d6e7845bb40790a\nhttps://git.kernel.org/stable/c/bef70ff9841990658610512b4a18e4a88c9b4df6\nhttps://git.kernel.org/stable/c/1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0",
    "id": "CVE-2026-45856",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux c3bea3d2dc5358e05541527283279102383b0231\nLinux Linux c3bea3d2dc5358e05541527283279102383b0231\nLinux Linux c3bea3d2dc5358e05541527283279102383b0231\nLinux Linux c3bea3d2dc5358e05541527283279102383b0231\nLinux Linux c3bea3d2dc5358e05541527283279102383b0231\nLinux Linux c3bea3d2dc5358e05541527283279102383b0231\nLinux Linux c3bea3d2dc5358e05541527283279102383b0231\nLinux Linux c3bea3d2dc5358e05541527283279102383b0231\nLinux Linux 5.0",
    "sourceHref": "",
    "cvss": {
        "score": 7.1,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "c3bea3d2dc5358e05541527283279102383b0231",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}