Bug 2532133 (CVE-2026-81002)

Summary: CVE-2026-81002 kernel: xdp: fix zero-copy frame layout
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's XDP (eXpress Data Path) component. Incorrect handling of zero-copy frame layout in the `xdp_convert_zc_to_xdp_frame()` function can allow an AF_XDP zero-copy packet, when redirected through `cpumap`, to cause a memory corruption. This can lead to a slab-out-of-bounds error, resulting in a kernel panic and a Denial of Service (DoS) for the system.
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Description OSIDB Bzimport 2026-09-11 20:49:40 UTC 
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 ...
Comment 1 Keith Grant 2026-09-14 20:20:59 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-81002.mbox