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RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send ib_uverbs_post_send() uses cmd.wqe_size from userspace without any validation before passing it to kmalloc() and using the allocated buffer as struct ib_uverbs_send_wr. If a user provides a small wqe_size value (e.g., 1), kmalloc() will succeed, but subsequent accesses to user_wr->opcode, user_wr->num_sge, and other fields will read beyond the allocated buffer, resulting in an out-of-bounds read from kernel heap memory. This could potentially leak sensitive kernel information to userspace. Additionally, providing an excessively large wqe_size can trigger a WARNING in the memory allocation path, as reported by syzkaller. This is inconsistent with ib_uverbs_unmarshall_recv() which properly validates that wqe_size >= sizeof(struct ib_uverbs_recv_wr) before proceeding. Add the same validation for ib_uverbs_post_send() to ensure wqe_size is at least sizeof(struct ib_uverbs_send_wr).

Announced Source revision 1
Original source ↗

CVE-2026-45856

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-45856

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "c3bea3d2dc5358e05541527283279102383b0231",
        "lessThan": "9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c3bea3d2dc5358e05541527283279102383b0231",
        "lessThan": "9b5ac1c15334d46c0dbd49d64a2257b929500163",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c3bea3d2dc5358e05541527283279102383b0231",
        "lessThan": "01c9b152647dc70dc06a4a2eff86ebb3b3c76075",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c3bea3d2dc5358e05541527283279102383b0231",
        "lessThan": "bf1feed1a7886af945f92890493aefd2b5c9928a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c3bea3d2dc5358e05541527283279102383b0231",
        "lessThan": "d533425ac1f2925b4fc3e4ed9b9d72362cb23475",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c3bea3d2dc5358e05541527283279102383b0231",
        "lessThan": "bf4454da8b1e712714628c0a0d6e7845bb40790a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c3bea3d2dc5358e05541527283279102383b0231",
        "lessThan": "bef70ff9841990658610512b4a18e4a88c9b4df6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c3bea3d2dc5358e05541527283279102383b0231",
        "lessThan": "1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/infiniband/core/uverbs_cmd.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.0"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.0",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.252",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.202",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.165",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.128",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.75",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.14",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "6.19.4",
        "versionType": "semver",
        "lessThanOrEqual": "6.19.*"
      },
      {
        "status": "unaffected",
        "version": "7.0",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/infiniband/core/uverbs_cmd.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-45856

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#40088 · Revision 1
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Publisher date
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