Cloudanix VulnDB

CVE-2026-80863

None

CVSS

—

EPSS

0.2%

Published

Sep 4, 2026

CISA due date

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Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in the Linux kernel's software RDMA code can let an attacker with special network access corrupt internal memory structures and potentially crash the machine or gain higher privileges.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Moderate
Impact
Privilege Gain
Component
OS kernel
Class
Memory Corruption
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Out-of-bounds write during slab free in RDMA RXE driver when free_rd_atomic_resources iterates using the newly updated qp->attr.max_dest_rd_atomic value before releasing the prior allocation, resulting in KASAN-detected slab corruption in rxe_qp_from_attr.

Why it matters to the business

Linux systems using software-emulated RDMA may suffer kernel memory corruption leading to crashes, denial of service, or potential local privilege escalation on hosts handling InfiniBand or RoCE traffic.

How an attack unfolds

An attacker with access to the RDMA uverbs interface invokes modify_qp with attribute changes that enlarge max_dest_rd_atomic; the driver then walks the old array using the new size during rxe_modify_qp, writing past the allocation and triggering the out-of-bounds condition.

How to fix it

Update the Linux kernel to a version containing the fix for ordering of max_dest_rd_atomic update versus old array release inside free_rd_atomic_resources and rxe_qp_from_attr.

How to confirm the fix worked

Confirm absence of the KASAN slab-out-of-bounds report in rxe_qp.c:163-180 after applying the patch; re-test attribute modification paths with fuzzers exercising QP attribute changes.

Typical attack path

  1. Obtain privileges allowing RDMA QP modification syscalls
  2. Allocate an RDMA queue pair via rxe driver
  3. Issue ib_uverbs_modify_qp with increased max_dest_rd_atomic
  4. Trigger rxe_qp_from_attr path that frees old atomic resources
  5. Cause slab out-of-bounds write caught by KASAN

How to detect it

Search kernel logs and crash reports for KASAN slab-out-of-bounds messages referencing free_rd_atomic_resources or rxe_qp_from_attr during RDMA QP attribute modification.

  • BUG: KASAN: slab-out-of-bounds in free_rd_atomic_resources
  • rxe_qp.c:180
  • rxe_qp_from_attr+0x1e88
  • Write of size 4 at addr .* by task .*
  • drivers/infiniband/sw/rxe/rxe_qp.c

What your security team should do

  • Prioritize kernel updates for any system exposing RDMA interfaces
  • Limit unprivileged access to /dev/infiniband/* devices where feasible
  • Enable KASAN or similar memory debugging on test systems to validate the fix
  • Review logs for prior occurrences of the described slab corruption

The record

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---

Affected packages

Ecosystem Package Introduced Fixed