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Linux Kernel EUVDEUVD-2026-53329

| CVE-2026-64582 HIGH
2026-08-05 Linux GHSA-9mqw-m8jv-5hmw
Linux Denial Of Service Canonical
7.8
CVSS 3.1 · Vendor: Linux
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Severity by source

Vendor (Linux) PRIMARY
7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI
7.0 HIGH

Race condition requires precise inter-CPU timing (AC:H); local user with RDMA device group access required (PR:L, AV:L); full kernel memory impact justified by confirmed page-level UAF primitive.

3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
4.0 AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
SUSE
6.4 MEDIUM
AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Red Hat
7.0 HIGH
qualitative

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

5
Analysis Generated
Aug 08, 2026 - 15:34 vuln.today
CVSS changed
Aug 08, 2026 - 15:22 NVD
7.8 (HIGH)
Patch available
Aug 05, 2026 - 12:01 EUVD
CVE Published
Aug 05, 2026 - 11:25 cve.org
HIGH 7.8
CVE Published
Aug 05, 2026 - 11:25 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

In the Linux kernel, the following vulnerability has been resolved:

RDMA/rxe: Fix a use-after-free problem in rxe_mmap

rxe_mmap() removes a rxe_mmap_info struct from the pending_mmaps list and releases pending_lock while the struct's kref is still at 1:

list_del_init(&ip->pending_mmaps); spin_unlock_bh(&rxe->pending_lock); /* ref == 1, no lock held */ ret = remap_vmalloc_range(vma, ip->obj, 0); /* walks PTEs */ [...] rxe_vma_open(vma); /* kref_get, ref → 2 */ remap_vmalloc_range_partial() walks PTEs without any lock.

A concurrent DESTROY_CQ ioctl on another CPU calls:

kref_put(&q->ip->ref, rxe_mmap_release) /* ref 1→0 */ vfree(ip->obj) /* clears vmalloc PTEs mid-walk */ kfree(ip) /* frees rxe_mmap_info */

This yields:

  1. Kernel crash, vmalloc_to_page() returns NULL when vfree wins the

per-PTE race -> vm_insert_page(NULL) → GPF in validate_page_before_insert

  1. Page UAF, vmalloc_to_page() reads a stale PTE before vfree clears

it. User VMA holds a PTE to a free'd page which might eventually get reallocated later by vmalloc which allows the attacker to get a clean page-level UAF.

It is worth noting that even though a page-level UAF is possible given the strong primitive, it is statistically very difficult to achieve given the very short time window (after the last insert_page and before the kref_get).

The call trace are as below:

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 UID: 1000 PID: 413 Comm: poc Not tainted 7.0.0-rc5-dirty #28 PREEMPT(lazy) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:validate_page_before_insert+0x32/0x300 Code: e5 41 57 41 56 49 89 fe 41 55 41 54 53 48 89 f3 e8 93 b5 a3 ff 48 8d 7b 08 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 7b 02 00 00 4c 8b 63 08 31 ff 4d 89 e5 41 83 e5 RSP: 0018:ffff88811b15f2f0 EFLAGS: 00000202 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000008 RBP: ffff88811b15f318 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881181eee00 R13: 0000000000000000 R14: ffff8881181eee00 R15: ffff8881181eee20 FS: 00007b1e000f76c0(0000) GS:ffff8884268e0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007b1e00a24ac0 CR3: 0000000116eb3000 CR4: 00000000000006f0 Call Trace: <TASK> insert_page+0x8f/0x190 ? __pfx_insert_page+0x10/0x10 ? kasan_save_alloc_info+0x38/0x60 vm_insert_page+0x2e7/0x400 remap_vmalloc_range_partial+0x212/0x3e0 remap_vmalloc_range+0x6e/0xb0 ? __kasan_check_write+0x14/0x30 rxe_mmap+0x2e9/0x5d0 ib_uverbs_mmap+0x1ad/0x2c0 __mmap_region+0x12c2/0x2ad0 ? __pfx___mmap_region+0x10/0x10 ? __sanitizer_cov_trace_switch+0x58/0xb0 ? mas_prev_slot+0x360/0x39c0 ? __sanitizer_cov_trace_switch+0x58/0xb0 ? mas_next_slot+0x1e5b/0x2f40 ? __sanitizer_cov_trace_cmp8+0x18/0x30 ? unmapped_area_topdown+0x4dd/0x610 ? kfree+0x1b1/0x440 ? free_cpumask_var+0x16/0x30 ? __kasan_slab_free+0x7d/0xa0 ? __sanitizer_cov_trace_cmp8+0x18/0x30 mmap_region+0x2e6/0x3c0 do_mmap+0xa3e/0x12a0 ? __pfx_do_mmap+0x10/0x10 ? __kasan_check_write+0x14/0x30 ? down_write_killable+0xba/0x160 ? __pfx_down_write_killable+0x10/0x10 ? __sanitizer_cov_trace_cmp4+0x16/0x30 vm_mmap_pgoff+0x2d4/0x4a0 ? __pfx_vm_mmap_pgoff+0x10/0x10 ? fget+0x1bf/0x270 ksys_mmap_pgoff+0x40c/0x690 ? __sanitizer_cov_trace_const_cmp4+0x16/0x30 ? __pfx_ksys_mmap_pgoff+0x10/0x10 ? __kasan_check_write+0x14/0x30 ? _raw_spin_trylock+0xbb/0x130 ? __pfx__raw_spin_trylock+0x10/0x10 __x64_sys_mmap+0x135/0x1e0 x64_sys_c ---truncated---

AnalysisAI

Use-after-free race condition in the Linux kernel's RDMA/rxe (SoftRoCE) subsystem allows a local unprivileged user to trigger a kernel crash or achieve page-level memory corruption. The race occurs between rxe_mmap() - which releases pending_lock while a rxe_mmap_info kref is still live - and a concurrent DESTROY_CQ ioctl that drops the kref to zero, causing vfree() to clear vmalloc PTEs mid-walk in remap_vmalloc_range_partial(). No CISA KEV listing exists and EPSS is 0.16% (5th percentile), reflecting the race's very narrow exploitation window; however, the C:H/I:H/A:H impact and confirmed upstream patch make this a priority update for any environment with RDMA/rxe loaded.

Technical ContextAI

The vulnerability is in rxe_mmap() within the Linux kernel's RDMA RXE subsystem (Soft RDMA over Ethernet / SoftRoCE), which implements InfiniBand semantics over standard Ethernet. The affected CPE is cpe:2.3:a:linux:linux across versions starting at commit 8700e3e7c4857d28ebaa824509934556da0b3e76. The root cause is a TOCTOU race (CWE-362: Concurrent Execution Using Shared Resource with Improper Synchronization; CWE-416: Use After Free): rxe_mmap() removes a rxe_mmap_info struct from the pending_mmaps list and releases pending_lock while the struct's kref is still 1. A concurrent DESTROY_CQ ioctl on another CPU calls kref_put() to 0, which triggers vfree(ip->obj) clearing vmalloc PTEs, followed by kfree(ip), while remap_vmalloc_range_partial() is still iterating those same PTEs without any lock held. This produces two outcomes: (1) a GPF kernel crash when vmalloc_to_page() returns NULL, leading to vm_insert_page(NULL) faulting in validate_page_before_insert; or (2) a page-level UAF where a stale PTE pointing to a freed vmalloc page is inserted into the user VMA, enabling that page to be reallocated by vmalloc and subsequently read or written by the attacker. The call trace confirms KASAN detection under a 7.0.0-rc5 kernel.

RemediationAI

Upgrade the Linux kernel to a patched release: 6.6.145, 6.12.97, 6.18.40, 7.1.5, or 7.2-rc1. Upstream fix commits are available at https://git.kernel.org/stable/c/665fb7d22a700c66a78db0cf88c6e6a649aba9d0, https://git.kernel.org/stable/c/e038d42cc09ca1da9d3568ce8ae062b2bfb3bc0e, https://git.kernel.org/stable/c/e59a6aa89e0fcd1d0707832eb4654fd9ae7d31e6, https://git.kernel.org/stable/c/3525987a392536f31a484833af258971af63b24c, and https://git.kernel.org/stable/c/35744ab3d03c5fca8c1752f53fc8fc674e14c561. For systems that cannot immediately patch, unloading the rdma_rxe module via 'modprobe -r rdma_rxe' eliminates the attack surface entirely, at the cost of disabling SoftRoCE functionality - acceptable if RDMA is not operationally required. Systems that do not use RDMA should blacklist the module in /etc/modprobe.d/ to prevent accidental future loading. Ubuntu-specific guidance should be sourced from Canonical's security advisories. Additional references: https://nvd.nist.gov/vuln/detail/CVE-2026-64582 and ENISA EUVD-2026-53329.

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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
openSUSE Tumbleweed Fixed
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected

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EUVD-2026-53329 vulnerability details – vuln.today
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