CVE-2026-45856 (GCVE-0-2026-45856)
Vulnerability from cvelistv5
Published
2026-05-27 12:15
Modified
2026-05-30 10:45
Severity ?
VLAI Severity ?
EPSS score ?
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).
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: c3bea3d2dc5358e05541527283279102383b0231 Version: c3bea3d2dc5358e05541527283279102383b0231 Version: c3bea3d2dc5358e05541527283279102383b0231 Version: c3bea3d2dc5358e05541527283279102383b0231 Version: c3bea3d2dc5358e05541527283279102383b0231 Version: c3bea3d2dc5358e05541527283279102383b0231 Version: c3bea3d2dc5358e05541527283279102383b0231 Version: c3bea3d2dc5358e05541527283279102383b0231 |
||
{
"containers": {
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"product": "Linux",
"programFiles": [
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],
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"vendor": "Linux",
"versions": [
{
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"version": "5.0"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.252",
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},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.202",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.165",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.128",
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},
{
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"status": "unaffected",
"version": "6.12.75",
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},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.14",
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},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.4",
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},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
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}
],
"negate": false,
"operator": "OR"
}
]
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],
"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-\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)."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.1,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
"version": "3.1"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-05-30T10:45:33.505Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"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"
}
],
"title": "RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-45856",
"datePublished": "2026-05-27T12:15:33.209Z",
"dateReserved": "2026-05-13T15:03:33.079Z",
"dateUpdated": "2026-05-30T10:45:33.505Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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