CVE-2026-74584 RDMA/bnxt_re: zero shared page before exposing to userspace
Local users with RDMA device access can read uninitialized kernel memory due to a missing zeroing operation in the bnxt_re driver.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74584?
CVE-2026-74584 is a high-severity vulnerability in Linux, published on 22 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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().
Which versions are affected by CVE-2026-74584?
How do I fix CVE-2026-74584?
Apply the vendor's patch.
Is CVE-2026-74584 being exploited?
There is no known exploitation of CVE-2026-74584 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74584, DEBIAN-CVE-2026-74584, GHSA-j6vr-r53f-g3jf, UBUNTU-CVE-2026-74584.