CVE-2026-81002
Received Received - Intake

Buffer Overflow in Linux Kernel XDP Zero-Copy Handling

Publication date: 2026-09-11

Last updated on: 2026-09-11

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: xdp: fix zero-copy frame layout xdp_convert_zc_to_xdp_frame() clones an XSK packet into an order-0 page and advertises PAGE_SIZE as its frame size. It allows the copied frame to occupy the page tail needed by skb_shared_info and records zero headroom even when metadata separates the frame header from packet data. An AF_XDP zero-copy packet redirected through cpumap can therefore make the skb overlap skb_shared_info or place it beyond the allocated page. Limit the copied layout to SKB_WITH_OVERHEAD(PAGE_SIZE) and include the metadata length in frame headroom. Redirect callers already handle a NULL conversion result. BUG: KASAN: slab-out-of-bounds in skb_gro_receive Write of size 4 at addr ffff88800cf37004 by task cpumap/1/map:1/146 Call Trace: skb_gro_receive (net/core/gro.c:174) udp_gro_receive (net/ipv4/udp_offload.c:812) inet_gro_receive (net/ipv4/af_inet.c:1539) dev_gro_receive (net/core/gro.c:515) gro_receive_skb (net/core/gro.c:633) cpu_map_kthread_run (kernel/bpf/cpumap.c:395) kthread (kernel/kthread.c:436) ret_from_fork (arch/x86/kernel/process.c:164) ret_from_fork_asm (arch/x86/entry/entry_64.S:255) Kernel panic - not syncing: KASAN: panic_on_warn set ...

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Meta Information

Published
2026-09-11
Last Modified
2026-09-11
Generated
2026-09-12
AI Q&A
2026-09-11
EPSS Evaluated
N/A
NVD
CVE-2026-81002
EUVD
EUVD-2026-76325

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a flaw in the XDP (eXpress Data Path) zero-copy mechanism. When an XSK packet is cloned into an order-0 page, it incorrectly advertises the full page size as the frame size. This allows the packet to overlap with skb_shared_info or place it beyond the allocated page, potentially causing memory corruption or crashes.

Detection Guidance

This vulnerability affects the Linux kernel's XDP (Express Data Path) and AF_XDP zero-copy functionality. Detection requires checking kernel logs for KASAN slab-out-of-bounds errors or kernel panics related to skb_gro_receive. Monitor system logs for crashes or warnings from the cpumap or XDP components.

Impact Analysis

This vulnerability could lead to system instability, crashes, or kernel panics. An attacker could exploit it to cause a denial-of-service (DoS) condition by triggering a slab-out-of-bounds write, corrupting kernel memory, or forcing a system reboot.

Mitigation Strategies

Apply the latest Linux kernel patches that address this issue. If patches are unavailable, disable AF_XDP zero-copy mode or XDP features temporarily. Monitor kernel updates from your distribution and restart affected services after applying fixes.

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