CVE-2026-45856 (GCVE-0-2026-45856)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:15 – Updated: 2026-05-27 12:15
VLAI
Title
RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send
Summary
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).
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: c3bea3d2dc5358e05541527283279102383b0231 , < 9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7 (git)
Affected: c3bea3d2dc5358e05541527283279102383b0231 , < 9b5ac1c15334d46c0dbd49d64a2257b929500163 (git)
Affected: c3bea3d2dc5358e05541527283279102383b0231 , < 01c9b152647dc70dc06a4a2eff86ebb3b3c76075 (git)
Affected: c3bea3d2dc5358e05541527283279102383b0231 , < bf1feed1a7886af945f92890493aefd2b5c9928a (git)
Affected: c3bea3d2dc5358e05541527283279102383b0231 , < d533425ac1f2925b4fc3e4ed9b9d72362cb23475 (git)
Affected: c3bea3d2dc5358e05541527283279102383b0231 , < bf4454da8b1e712714628c0a0d6e7845bb40790a (git)
Affected: c3bea3d2dc5358e05541527283279102383b0231 , < bef70ff9841990658610512b4a18e4a88c9b4df6 (git)
Affected: c3bea3d2dc5358e05541527283279102383b0231 , < 1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0 (git)
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Linux Linux Affected: 5.0
Unaffected: 0 , < 5.0 (semver)
Unaffected: 5.10.252 , ≤ 5.10.* (semver)
Unaffected: 5.15.202 , ≤ 5.15.* (semver)
Unaffected: 6.1.165 , ≤ 6.1.* (semver)
Unaffected: 6.6.128 , ≤ 6.6.* (semver)
Unaffected: 6.12.75 , ≤ 6.12.* (semver)
Unaffected: 6.18.14 , ≤ 6.18.* (semver)
Unaffected: 6.19.4 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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            "drivers/infiniband/core/uverbs_cmd.c"
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          "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-\u003eopcode, user_wr-\u003enum_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 \u003e= 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)."
        }
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      "providerMetadata": {
        "dateUpdated": "2026-05-27T12:15:33.209Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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    "dateReserved": "2026-05-13T15:03:33.079Z",
    "dateUpdated": "2026-05-27T12:15:33.209Z",
    "state": "PUBLISHED"
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  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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