CVE-2026-74584
Received Received - Intake

Memory Leak in Linux Kernel RDMA/bnxt_re Driver

Publication date: 2026-08-22

Last updated on: 2026-08-22

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: RDMA/bnxt_re: zero shared page before exposing to userspace bnxt_re_alloc_ucontext() allocates uctx->shpg via __get_free_page(GFP_KERNEL). The buddy allocator does not zero pages without __GFP_ZERO, so the page contains stale kernel data from whatever object most recently freed it. The page is then mapped into userspace via vm_insert_page() under BNXT_RE_MMAP_SH_PAGE in bnxt_re_mmap(). The driver only ever writes 4 bytes (a u32 AVID) at offset BNXT_RE_AVID_OFFT (0x10) inside bnxt_re_create_ah(); the remaining 4092 bytes of the page are exposed to userspace unsanitised, leaking kernel memory contents. Any user with access to /dev/infiniband/uverbsX on a host with a bnxt_re device (typically rdma group membership) can read this data via a single mmap() at pgoff 0 after IB_USER_VERBS_CMD_GET_CONTEXT. Other shared pages in the same file already use get_zeroed_page() correctly: drivers/infiniband/hw/bnxt_re/ib_verbs.c srq->uctx_srq_page = (void *)get_zeroed_page(GFP_KERNEL); cq->uctx_cq_page = (void *)get_zeroed_page(GFP_KERNEL); uctx->shpg is the only outlier. Bring it in line with the existing convention by switching to get_zeroed_page().

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Meta Information

Published
2026-08-22
Last Modified
2026-08-22
Generated
2026-08-22
AI Q&A
2026-08-22
EPSS Evaluated
N/A
NVD
CVE-2026-74584
EUVD
EUVD-2026-64332

Affected Vendors & Products

Currently, no data is known.

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a memory exposure vulnerability in the Linux kernel's RDMA driver for Broadcom NetXtreme-C/E devices (bnxt_re). A shared page allocated via __get_free_page() is not zeroed before being mapped into userspace, potentially leaking sensitive kernel memory contents.

Detection Guidance

This vulnerability can be detected by checking for the presence of the bnxt_re driver and examining memory exposure via /dev/infiniband/uverbsX. Look for uninitialized memory leaks in shared pages mapped by users with rdma group access.

Impact Analysis

Any user with access to /dev/infiniband/uverbsX on affected systems can read kernel memory by mapping the shared page via mmap(). This could expose sensitive data like passwords, encryption keys, or other confidential information from the kernel.

Compliance Impact

This vulnerability could lead to unauthorized data exposure, potentially violating confidentiality requirements in GDPR, HIPAA, and other regulations. Organizations may face compliance violations if sensitive data is leaked through this flaw.

Mitigation Strategies

Apply the Linux kernel patch that replaces __get_free_page() with get_zeroed_page() in bnxt_re_alloc_ucontext(). Restrict access to /dev/infiniband/uverbsX to trusted users only until patched.

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