RDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe

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.

Timeline

1. Aug 15, 2026, 5:58 AM UTCCVE published
2. Oct 16, 2026, 6:54 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Oct 16, 2026, 6:55 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 8700e3e7c4857d28ebaa824509934556da0b3e76 · fixed in c8db0e5ab0b6c540214c46c56aaac7cbcb0967fe; From 8700e3e7c4857d28ebaa824509934556da0b3e76 · fixed in e48daa94ad2d406225b73491fc935064716f0ec7; From 8700e3e7c4857d28ebaa824509934556da0b3e76 · fixed in 3cfa2a3adc51b7c57729961a03446962ff10e3d2; From 8700e3e7c4857d28ebaa824509934556da0b3e76 · fixed in cd19a6345e3727adafafa5954b58b13c92e13b80; From 8700e3e7c4857d28ebaa824509934556da0b3e76 · fixed in 3e07ea9579dc9553d2285c26c2823931358aa3b8; From 8700e3e7c4857d28ebaa824509934556da0b3e76 · fixed in 02558c86b6b761063e9399e6b939984500327ef1; From 8700e3e7c4857d28ebaa824509934556da0b3e76 · fixed in b9800d7953d119bcc068c74587d48e4ba0313629; From 8700e3e7c4857d28ebaa824509934556da0b3e76 · fixed in 22b8fbded65b8c441b634a185f8da67657df6c50

• Linux Linux

  4.8

• KernelLinux

  From 4.8.0 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.178; From 6.2.0 · fixed in 6.6.145; From 6.7.0 · fixed in 6.12.97; From 6.13.0 · fixed in 6.18.40; From 6.19.0 · fixed in 7.1.5

References 8