---
id: CVE-2025-21961
title: 'eth: bnxt: fix truesize for mb-xdp-pass case'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  eth: bnxt: fix truesize for mb-xdp-pass case

  When mb-xdp is set and return is XDP_PASS, packet is converted from
  xdp_buff to sk_buff with xdp_update_skb_shared_info() …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 <
    01492e94a823c50f4ab5084e3ac210ba981133be
  - >-
    Linux >= 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 <
    924ef5959b7cfbee8f923a77b0ad19b5f0a4d526
  - >-
    Linux >= 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 <
    19107e71be330dbccb9f8f9f4cf0a9abeadad802
  - >-
    Linux >= 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 <
    b4679807c6083ade4d47f03f80da891afcb6ef62
  - >-
    Linux >= 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 <
    9f7b2aa5034e24d3c49db73d5f760c0435fe31c2
  - Linux 5.19
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2025-10-01T17:15:46.557576Z'
published: '2025-04-01'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T12:21:03.937Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-21961'
references:
  - url: 'https://git.kernel.org/stable/c/01492e94a823c50f4ab5084e3ac210ba981133be'
  - url: 'https://git.kernel.org/stable/c/924ef5959b7cfbee8f923a77b0ad19b5f0a4d526'
  - url: 'https://git.kernel.org/stable/c/19107e71be330dbccb9f8f9f4cf0a9abeadad802'
  - url: 'https://git.kernel.org/stable/c/b4679807c6083ade4d47f03f80da891afcb6ef62'
  - url: 'https://git.kernel.org/stable/c/9f7b2aa5034e24d3c49db73d5f760c0435fe31c2'
tags:
  - cve.org
epss: 0.0059
epssPercentile: 0.48202
ingestedAt: '2026-10-21T12:48:53.717Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

eth: bnxt: fix truesize for mb-xdp-pass case

When mb-xdp is set and return is XDP_PASS, packet is converted from
xdp_buff to sk_buff with xdp_update_skb_shared_info() in
bnxt_xdp_build_skb().
bnxt_xdp_build_skb() passes incorrect truesize argument to
xdp_update_skb_shared_info().
The truesize is calculated as BNXT_RX_PAGE_SIZE * sinfo->nr_frags but
the skb_shared_info was wiped by napi_build_skb() before.
So it stores sinfo->nr_frags before bnxt_xdp_build_skb() and use it
instead of getting skb_shared_info from xdp_get_shared_info_from_buff().

Splat looks like:
 ------------[ cut here ]------------
 WARNING: CPU: 2 PID: 0 at net/core/skbuff.c:6072 skb_try_coalesce+0x504/0x590
 Modules linked in: xt_nat xt_tcpudp veth af_packet xt_conntrack nft_chain_nat xt_MASQUERADE nf_conntrack_netlink xfrm_user xt_addrtype nft_coms
 CPU: 2 UID: 0 PID: 0 Comm: swapper/2 Not tainted 6.14.0-rc2+ #3
 RIP: 0010:skb_try_coalesce+0x504/0x590
 Code: 4b fd ff ff 49 8b 34 24 40 80 e6 40 0f 84 3d fd ff ff 49 8b 74 24 48 40 f6 c6 01 0f 84 2e fd ff ff 48 8d 4e ff e9 25 fd ff ff <0f> 0b e99
 RSP: 0018:ffffb62c4120caa8 EFLAGS: 00010287
 RAX: 0000000000000003 RBX: ffffb62c4120cb14 RCX: 0000000000000ec0
 RDX: 0000000000001000 RSI: ffffa06e5d7dc000 RDI: 0000000000000003
 RBP: ffffa06e5d7ddec0 R08: ffffa06e6120a800 R09: ffffa06e7a119900
 R10: 0000000000002310 R11: ffffa06e5d7dcec0 R12: ffffe4360575f740
 R13: ffffe43600000000 R14: 0000000000000002 R15: 0000000000000002
 FS:  0000000000000000(0000) GS:ffffa0755f700000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007f147b76b0f8 CR3: 00000001615d4000 CR4: 00000000007506f0
 PKRU: 55555554
 Call Trace:
  <IRQ>
  ? __warn+0x84/0x130
  ? skb_try_coalesce+0x504/0x590
  ? report_bug+0x18a/0x1a0
  ? handle_bug+0x53/0x90
  ? exc_invalid_op+0x14/0x70
  ? asm_exc_invalid_op+0x16/0x20
  ? skb_try_coalesce+0x504/0x590
  inet_frag_reasm_finish+0x11f/0x2e0
  ip_defrag+0x37a/0x900
  ip_local_deliver+0x51/0x120
  ip_sublist_rcv_finish+0x64/0x70
  ip_sublist_rcv+0x179/0x210
  ip_list_rcv+0xf9/0x130

How to reproduce:
<Node A>
ip link set $interface1 xdp obj xdp_pass.o
ip link set $interface1 mtu 9000 up
ip a a 10.0.0.1/24 dev $interface1
<Node B>
ip link set $interfac2 mtu 9000 up
ip a a 10.0.0.2/24 dev $interface2
ping 10.0.0.1 -s 65000

Following ping.py patch adds xdp-mb-pass case. so ping.py is going to be
able to reproduce this issue.

## Affected

- `Linux >= 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 < 01492e94a823c50f4ab5084e3ac210ba981133be`
- `Linux >= 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 < 924ef5959b7cfbee8f923a77b0ad19b5f0a4d526`
- `Linux >= 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 < 19107e71be330dbccb9f8f9f4cf0a9abeadad802`
- `Linux >= 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 < b4679807c6083ade4d47f03f80da891afcb6ef62`
- `Linux >= 1dc4c557bfedfcdf7fc0c46795857773b7ad66e7 < 9f7b2aa5034e24d3c49db73d5f760c0435fe31c2`
- `Linux 5.19`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.