CVE-2026-74378 (GCVE-0-2026-74378)
Vulnerability from cvelistv5
Published
2026-08-15 05:58
Modified
2026-08-17 05:46
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
RDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe
get_srq_wqe() reads wqe->dma.num_sge from the shared receive queue
buffer, which is mapped into userspace. It validates num_sge against
max_sge, but then re-reads the same field to calculate the memcpy
size. A concurrent userspace thread can modify num_sge between
validation and use, causing a heap buffer overflow when copying the
WQE into qp->resp.srq_wqe.
Read num_sge into a local variable and use it for both the bounds
check and the size calculation.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 8700e3e7c4857d28ebaa824509934556da0b3e76 Version: 8700e3e7c4857d28ebaa824509934556da0b3e76 Version: 8700e3e7c4857d28ebaa824509934556da0b3e76 Version: 8700e3e7c4857d28ebaa824509934556da0b3e76 Version: 8700e3e7c4857d28ebaa824509934556da0b3e76 Version: 8700e3e7c4857d28ebaa824509934556da0b3e76 |
||
{
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{
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{
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"version": "6.12.97",
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{
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"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe\n\nget_srq_wqe() reads wqe-\u003edma.num_sge from the shared receive queue\nbuffer, which is mapped into userspace. It validates num_sge against\nmax_sge, but then re-reads the same field to calculate the memcpy\nsize. A concurrent userspace thread can modify num_sge between\nvalidation and use, causing a heap buffer overflow when copying the\nWQE into qp-\u003eresp.srq_wqe.\n\nRead num_sge into a local variable and use it for both the bounds\ncheck and the size calculation."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - Exploitation requires a local process with mmap write access to the SRQ receive queue shared with the kernel; although incoming RoCE/UDP packets trigger get_srq_wqe(), a remote peer cannot modify num_sge in the victim\u0027s userspace-mapped WQE buffer, so the TOCTOU overflow cannot be achieved from the network alone.\nAC:L - The attacker controls both sides of the race: a userspace thread that repeatedly rewrites num_sge in the mmap\u0027d SRQ entry and the thread/process that posts recv WQEs and receives the triggering RoCE Send/Write packet, making the TOCTOU window reliably winnable without external timing luck.\nPR:L - An unprivileged local user with access to /dev/infiniband/uverbs can create an SRQ (mmap\u0027d queue), associate a QP, and post recv buffers via ibverbs; rxe device setup via \"rdma link add type rxe\" is reachable with CAP_NET_ADMIN inside a user namespace (unshare -Urn).\nUI:N - No victim user interaction is required; the attacker operates their own malicious RDMA userspace process and can self-trigger the vulnerable responder path with RoCE request packets once SRQ/QP resources are configured.\nS:U - The heap overflow corrupts kernel memory within the rxe_qp responder context on the same host kernel, enabling local privilege escalation rather than crossing a VM, container, or IOMMU security boundary to impact a different authority.\nC:H - The attacker-controlled memcpy size causes an out-of-bounds copy from the mmap\u0027d SRQ ring buffer and overflows the fixed qp-\u003eresp.srq_wqe kernel buffer, enabling adjacent kernel heap data disclosure and providing primitives that can be developed into arbitrary kernel memory reads.\nI:H - Overflowing qp-\u003eresp.srq_wqe corrupts subsequent fields in rxe_resp_info/rxe_qp (e.g., responder resource pointers and state), giving a kernel heap buffer overflow that can be leveraged for arbitrary kernel memory writes and local privilege escalation.\nA:H - Corrupting responder state inside rxe_qp can cause kernel oops/panic or wedged RDMA processing during packet handling; even failed exploitation attempts can crash the kernel through use of corrupted function pointers and queue state."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:46:30.843Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/3cfa2a3adc51b7c57729961a03446962ff10e3d2"
},
{
"url": "https://git.kernel.org/stable/c/cd19a6345e3727adafafa5954b58b13c92e13b80"
},
{
"url": "https://git.kernel.org/stable/c/3e07ea9579dc9553d2285c26c2823931358aa3b8"
},
{
"url": "https://git.kernel.org/stable/c/02558c86b6b761063e9399e6b939984500327ef1"
},
{
"url": "https://git.kernel.org/stable/c/b9800d7953d119bcc068c74587d48e4ba0313629"
},
{
"url": "https://git.kernel.org/stable/c/22b8fbded65b8c441b634a185f8da67657df6c50"
}
],
"title": "RDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe",
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"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74378",
"datePublished": "2026-08-15T05:58:56.381Z",
"dateReserved": "2026-08-15T05:44:03.890Z",
"dateUpdated": "2026-08-17T05:46:30.843Z",
"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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