CVE-2026-80863
Received Received - Intake

Heap Out-of-Bounds Write in Linux Kernel RDMA/rxe

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: kernel.org

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---

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Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-25
AI Q&A
2026-09-04
EPSS Evaluated
2026-09-23
NVD
CVE-2026-80863
EUVD
EUVD-2026-71313

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
linux_kernel linux_kernel 7.1.0
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a Linux kernel vulnerability in the RDMA/rxe subsystem. It occurs when free_rd_atomic_resources() uses qp->attr.max_dest_rd_atomic to iterate while updating max_dest_rd_atomic before freeing the old array. This causes the free path to access memory outside the allocated slab, leading to a slab out-of-bounds write detected by KASAN.

Detection Guidance

This vulnerability is specific to the Linux kernel's RDMA/rxe subsystem and may trigger KASAN slab-out-of-bounds errors. Check kernel logs for KASAN reports indicating slab-out-of-bounds writes in rxe_qp.c or related RDMA modules. Use commands like dmesg | grep -i kasan or journalctl -k | grep -i kasan to search for such errors.

Impact Analysis

This vulnerability could allow an attacker with local access to cause a kernel crash or execute arbitrary code with kernel privileges. It may lead to denial of service or privilege escalation on systems using the RDMA/rxe subsystem.

Compliance Impact

This vulnerability is a memory corruption issue in the Linux kernel's RDMA subsystem that could lead to unauthorized memory access or crashes. While not directly tied to data protection regulations, such vulnerabilities could potentially impact compliance by compromising system integrity or enabling data exfiltration if exploited. However, specific compliance impacts depend on deployment context and mitigations.

Mitigation Strategies

Update your Linux kernel to a version that includes the fix for this vulnerability. Since this is a kernel-level issue, patching the kernel is the primary mitigation. Monitor kernel security advisories for updates addressing CVE-2026-80863.

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