---
id: CVE-2026-98271
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: skbuff: do not leave stale header offsets after pskb_carve()

  pskb_carve_inside_header() and pskb_carve_inside_nonlinear() remove
  the first bytes of a packet and r…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: skbuff: do not leave stale header offsets after pskb_carve()

  pskb_carve_inside_header() and pskb_carve_inside_nonlinear() remove
  the first bytes of a packet and r…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 6fa01ccd883021105e9f8af7d04b9f156fa3494a <
    75e4a3e62531738c124c8555a626426fca29d392
  - >-
    Linux >= 6fa01ccd883021105e9f8af7d04b9f156fa3494a <
    bff8a8e53a6d290bc2777bde36d3cb6317b8463d
  - >-
    Linux >= 6fa01ccd883021105e9f8af7d04b9f156fa3494a <
    12929ed66a5166177ef5f06d3da81e4f99993e90
  - >-
    Linux >= 6fa01ccd883021105e9f8af7d04b9f156fa3494a <
    a5117e1eccac6ee3bd4aed7cacf8ebcb6b3eb309
  - Linux 4.7
published: '2026-10-06'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T09:18:16.627'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98271'
references:
  - url: 'https://git.kernel.org/stable/c/12929ed66a5166177ef5f06d3da81e4f99993e90'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/75e4a3e62531738c124c8555a626426fca29d392'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a5117e1eccac6ee3bd4aed7cacf8ebcb6b3eb309'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bff8a8e53a6d290bc2777bde36d3cb6317b8463d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-06T08:50:17.426Z'
---

## Overview

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

net: skbuff: do not leave stale header offsets after pskb_carve()

pskb_carve_inside_header() and pskb_carve_inside_nonlinear() remove
the first bytes of a packet and reallocate skb->head.

All the headers that were present before the operation are gone,
but both functions call skb_headers_offset_update(skb, 0), which
is a no-op : skb->mac_header, skb->network_header,
skb->transport_header and skb->csum_start keep their old values and
now describe bytes which are no longer there.

Both helpers size the new head from the old skb_end_offset(), so the
stale offsets still land inside the new allocation. They point past
skb_tail_pointer() though, to bytes that were never initialized.

pskb_carve_inside_nonlinear() is the worst case, because it leaves a
zombie skb with an empty linear part (skb->data ==
skb_tail_pointer(skb), skb_headlen(skb) == 0), while
skb_mac_header_was_set() is still true and skb->mac_header is way
ahead of skb->data.

The only user of pskb_extract() is rds_tcp_data_recv(), and the
carved skb is queued on tinc->ti_skb_list. When the RDS incoming
message is released, rds_tcp_inc_free() calls skb_queue_purge(),
which frees the skbs with SKB_DROP_REASON_QUEUE_PURGE. This is
visible from drop_monitor, which then tries to pull back to the
(bogus) mac header :

skbuff: __skb_pull(len=234)
skb len=6968 data_len=6968 headroom=0 headlen=0 tailroom=0
end-tail=384 mac=(234,14) mac_len=14 net=(248,40) trans=288
shinfo(txflags=0 nr_frags=1 gso(size=1428 type=16 segs=5))
csum(0x100120 start=288 offset=16 ip_summed=3 complete_sw=0 valid=1 level=0)
hash(0x7b446c6c sw=0 l4=1) proto=0x86dd pkttype=0 iif=60
kernel BUG at ./include/linux/skbuff.h:2847!

Add skb_carve_reset_headers() to mark the mac and transport headers
as not set, reset the network header, clear skb->mac_len, and drop
a now meaningless CHECKSUM_PARTIAL (csum_start no longer describes
anything).

Invalidate the inner offsets as well. Unlike mac_header and
transport_header they have no "unset" sentinel, so a leftover
non-zero value still looks like a real header. Zero
skb->inner_mac_header, skb->inner_network_header,
skb->inner_transport_header, skb->inner_protocol and
skb->encapsulation, so that all the header state is invalidated in
one place.

v2: fixed an inaccurate changelog. The stale offsets stay inside the
    new skb->head, which is never smaller than the old one, they
    simply point past skb_tail_pointer() to bytes that are gone.
    Thanks to Xuanqiang Luo for insisting on this.
    Also invalidate the inner header state, as suggested by the
    netdev AI review :
    https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260911114922.621937-1-edumazet%40google.com

## Remediation

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