CVE-2026-80863 RDMA/rxe: Fix OOB in free_rd_atomic_resources()
A local attacker with low privileges can trigger a slab out-of-bounds write in the Linux kernel RDMA subsystem, potentially leading to code execution or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80863?
CVE-2026-80863 is a memory corruption vulnerability in Linux, published on 4 Sep 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/rxe: Fix OOB in free_rd_atomic_resources()
free_rd_atomic_resources() iterates using qp->attr.max_dest_rd_atomic. Updating max_dest_rd_atomic before freeing the old array can make the free path walk past the old allocation and trigger a slab out-of-bounds write catched by KASAN: ================================================================== BUG: KASAN: slab-out-of-bounds in free_rd_atomic_resource drivers/infiniband/sw/rxe/rxe_qp.c:180 [inline] BUG: KASAN: slab-out-of-bounds in free_rd_atomic_resources drivers/infiniband/sw/rxe/rxe_qp.c:171 [inline] BUG: KASAN: slab-out-of-bounds in free_rd_atomic_resources drivers/infiniband/sw/rxe/rxe_qp.c:163 [inline] BUG: KASAN: slab-out-of-bounds in rxe_qp_from_attr+0x1e88/0x2150 drivers/infiniband/sw/rxe/rxe_qp.c:712 Write of size 4 at addr ffff88802b8dddb8 by task syz.3.451/11063
CPU: 0 UID: 0 PID: 11063 Comm: syz.3.451 Not tainted 7.1.0 #2 PREEMPT(full) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x10e/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xf7/0x600 mm/kasan/report.c:482 kasan_report+0xe4/0x120 mm/kasan/report.c:595 free_rd_atomic_resource drivers/infiniband/sw/rxe/rxe_qp.c:180 [inline] free_rd_atomic_resources drivers/infiniband/sw/rxe/rxe_qp.c:171 [inline] free_rd_atomic_resources drivers/infiniband/sw/rxe/rxe_qp.c:163 [inline] rxe_qp_from_attr+0x1e88/0x2150 drivers/infiniband/sw/rxe/rxe_qp.c:712 rxe_modify_qp+0x1e2/0x530 drivers/infiniband/sw/rxe/rxe_verbs.c:623 ib_security_modify_qp+0x223/0xfa0 drivers/infiniband/core/security.c:625 _ib_modify_qp+0x333/0xec0 drivers/infiniband/core/verbs.c:1915 modify_qp+0x13ca/0x1940 drivers/infiniband/core/uverbs_cmd.c:1932 ib_uverbs_modify_qp+0xcb/0x120 drivers/infiniband/core/uverbs_cmd.c:1958 ib_uverbs_write+0xb86/0x1030 drivers/infiniband/core/uverbs_main.c:680 vfs_write+0x2aa/0x1070 fs/read_write.c:686 ksys_write+0x1f8/0x250 fs/read_write.c:740 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x116/0x800 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fefc75a70cd Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fefc8495018 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fefc7835fa0 RCX: 00007fefc75a70cd RDX: 0000000000000078 RSI: 0000200000000240 RDI: 0000000000000007 RBP: 00007fefc764f10f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fefc7836038 R14: 00007fefc7835fa0 R15: 00007ffcf0586aa0 </TASK>
Allocated by task 11063: kasan_save_stack+0x33/0x60 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:398 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5296 [inline] __kmalloc_noprof+0x32a/0x850 mm/slub.c:5308 kmalloc_noprof include/linux/slab.h:954 [inline] kzalloc_noprof include/linux/slab.h:1188 [inline] alloc_rd_atomic_resources drivers/infiniband/sw/rxe/rxe_qp.c:155 [inline] rxe_qp_from_attr+0x3f8/0x2150 drivers/infiniband/sw/rxe/rxe_qp.c:714 rxe_modify_qp+0x1e2/0x530 drivers/infiniband/sw/rxe/rxe_verbs.c:623 ib_security_modify_qp+0x223/0xfa0 drivers/infiniband/core/security.c:625 _ib_modify_qp+0x333/0xec0 drivers/infiniband/core/verbs.c:1915 modify_qp+0x13ca/0x1940 drivers/infiniband/core/uverbs_cmd.c:1932 ib_uverbs_modify_qp+0xcb/0x120 drivers/infiniband/core/uverbs_cmd.c:1958 ib_uverbs_write+0xb86/0x1030 drivers/infiniband/core/uverbs_ma ---truncated---
Which versions are affected by CVE-2026-80863?
How do I fix CVE-2026-80863?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-80863 being exploited?
There is no known exploitation of CVE-2026-80863 in the wild and no public exploit code.
Sources
Also known as AZL-99618, BELL-CVE-2026-80863, DEBIAN-CVE-2026-80863, GHSA-h28p-6hx4-vcc6, UBUNTU-CVE-2026-80863.