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CVE-2026-64582— RDMA/rxe: Fix a use-after-free problem in rxe_mmap

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 4.8版本存在安全漏洞,该漏洞源于RDMA/rxe的rxe_mmap函数存在释放后重用问题,可能导致内核崩溃或页面释放后重用。

CVSS 7.8 · High EPSS 0.13% · P2

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 8700e3e7c4857d28ebaa824509934556da0b3e76< b810352d0916796dabe633cdb9adee9863ab4911 affected
8700e3e7c4857d28ebaa824509934556da0b3e76< aef5ea8578f97f2701039600846a8bcf5f21e863 affected
8700e3e7c4857d28ebaa824509934556da0b3e76< 3371f2036e0f970166bbb624e25bba46d32fa18e affected
8700e3e7c4857d28ebaa824509934556da0b3e76< 665fb7d22a700c66a78db0cf88c6e6a649aba9d0 affected
8700e3e7c4857d28ebaa824509934556da0b3e76< e038d42cc09ca1da9d3568ce8ae062b2bfb3bc0e affected
8700e3e7c4857d28ebaa824509934556da0b3e76< e59a6aa89e0fcd1d0707832eb4654fd9ae7d31e6 affected
8700e3e7c4857d28ebaa824509934556da0b3e76< 3525987a392536f31a484833af258971af63b24c affected
8700e3e7c4857d28ebaa824509934556da0b3e76< 35744ab3d03c5fca8c1752f53fc8fc674e14c561 affected
… +10 more rows
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I. Basic Information for CVE-2026-64582

Vulnerability Information

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Vulnerability Title
RDMA/rxe: Fix a use-after-free problem in rxe_mmap
Source: CVE Program / CVE List V5
Vulnerability Description
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 2. 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---
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一款操作系统内核。 Linux kernel 4.8版本存在安全漏洞,该漏洞源于RDMA/rxe的rxe_mmap函数存在释放后重用问题,可能导致内核崩溃或页面释放后重用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 8700e3e7c4857d28ebaa824509934556da0b3e76 ~ b810352d0916796dabe633cdb9adee9863ab4911 -
Linux Linux 4.8 -

II. Public POCs for CVE-2026-64582

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III. Intelligence Information for CVE-2026-64582

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Patches & Fixes for CVE-2026-64582 (8)

Same Patch Batch · Linux · 2026-08-05 · 17 CVEs total

CVE-2026-64566 9.8 CRITICAL xfrm: iptfs: propagate SKBFL_SHARED_FRAG in iptfs_skb_add_frags()
CVE-2026-64578 8.2 HIGH ksmbd: validate compound request size before reading StructureSize2
CVE-2026-64567 7.8 HIGH btrfs: reject free space cache with more entries than pages
CVE-2026-64568 7.8 HIGH wifi: mac80211: fix unsol_bcast_probe_resp double free on alloc failure
CVE-2026-64570 7.8 HIGH wifi: mac80211: fix fils_discovery double free on alloc failure
CVE-2026-64574 7.8 HIGH wifi: mac80211: tear down new links on vif update error path
CVE-2026-64575 7.8 HIGH bpf: tcp: fix double sock release on batch realloc
CVE-2026-64580 7.8 HIGH xfrm6: clear dst.dev on error to avoid double netdev_put in xfrm6_fill_dst()
CVE-2026-64581 7.8 HIGH xfrm: fix sk_dst_cache double-free in xfrm_user_policy()
CVE-2026-64577 7.5 HIGH gtp: check skb_pull_data() return in gtp1u_send_echo_resp()
CVE-2026-64576 7.1 HIGH nexthop: initialize extack in nh_res_bucket_migrate()
CVE-2026-64569 mpls: fix NULL deref in mpls_valid_fib_dump_req() on CONFIG_INET=n
CVE-2026-64571 wifi: p54: validate RX frame length in p54_rx_eeprom_readback()
CVE-2026-64572 ipv4: fib: free fib_alias with kfree_rcu() on insert error path
CVE-2026-64573 Bluetooth: qca: fix NVM tag length underflow in TLV parser
CVE-2026-64579 xfrm: policy: preallocate inexact bins before xfrm_hash_rebuild reinsert

IV. Related Vulnerabilities

V. Comments for CVE-2026-64582

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