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

net: core: remove unnecessary frame_sz check in bpf_xdp_adjust_tail()

Syzkaller reported the following issue:
=======================================
Too BIG xdp->frame_sz = 131072
WARNING: CPU: 0 PID: 5020 at net/core/filter.c:4121
____bpf_xdp_adjust_tail net/core/filter.c:4121 [inline]
WARNING: CPU: 0 PID: 5020 at net/core/filter.c:4121
bpf_xdp_adjust_tail+0x466/0xa10 net/core/filter.c:4103
...
Call Trace:
<TASK>
bpf_prog_4add87e5301a4105+0x1a/0x1c
__bpf_prog_run include/linux/filter.h:600 [inline]
bpf_prog_run_xdp include/linux/filter.h:775 [inline]
bpf_prog_run_generic_xdp+0x57e/0x11e0 net/core/dev.c:4721
netif_receive_generic_xdp net/core/dev.c:4807 [inline]
do_xdp_generic+0x35c/0x770 net/core/dev.c:4866
tun_get_user+0x2340/0x3ca0 drivers/net/tun.c:1919
tun_chr_write_iter+0xe8/0x210 drivers/net/tun.c:2043
call_write_iter include/linux/fs.h:1871 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x650/0xe40 fs/read_write.c:584
ksys_write+0x12f/0x250 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

xdp->frame_sz > PAGE_SIZE check was introduced in commit c8741e2bfe87
("xdp: Allow bpf_xdp_adjust_tail() to grow packet size"). But Jesper
Dangaard Brouer <jbrouer@redhat.com> noted that after introducing the
xdp_init_buff() which all XDP driver use - it's safe to remove this
check. The original intend was to catch cases where XDP drivers have
not been updated to use xdp.frame_sz, but that is not longer a concern
(since xdp_init_buff).

Running the initial syzkaller repro it was discovered that the
contiguous physical memory allocation is used for both xdp paths in
tun_get_user(), e.g. tun_build_skb() and tun_alloc_skb(). It was also
stated by Jesper Dangaard Brouer <jbrouer@redhat.com> that XDP can
work on higher order pages, as long as this is contiguous physical
memory (e.g. a page).
Published: 2025-12-24
Score: 7.0 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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History

Thu, 25 Dec 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate

Wed, 24 Dec 2025 13:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net: core: remove unnecessary frame_sz check in bpf_xdp_adjust_tail() Syzkaller reported the following issue: ======================================= Too BIG xdp->frame_sz = 131072 WARNING: CPU: 0 PID: 5020 at net/core/filter.c:4121 ____bpf_xdp_adjust_tail net/core/filter.c:4121 [inline] WARNING: CPU: 0 PID: 5020 at net/core/filter.c:4121 bpf_xdp_adjust_tail+0x466/0xa10 net/core/filter.c:4103 ... Call Trace: <TASK> bpf_prog_4add87e5301a4105+0x1a/0x1c __bpf_prog_run include/linux/filter.h:600 [inline] bpf_prog_run_xdp include/linux/filter.h:775 [inline] bpf_prog_run_generic_xdp+0x57e/0x11e0 net/core/dev.c:4721 netif_receive_generic_xdp net/core/dev.c:4807 [inline] do_xdp_generic+0x35c/0x770 net/core/dev.c:4866 tun_get_user+0x2340/0x3ca0 drivers/net/tun.c:1919 tun_chr_write_iter+0xe8/0x210 drivers/net/tun.c:2043 call_write_iter include/linux/fs.h:1871 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x650/0xe40 fs/read_write.c:584 ksys_write+0x12f/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd xdp->frame_sz > PAGE_SIZE check was introduced in commit c8741e2bfe87 ("xdp: Allow bpf_xdp_adjust_tail() to grow packet size"). But Jesper Dangaard Brouer <jbrouer@redhat.com> noted that after introducing the xdp_init_buff() which all XDP driver use - it's safe to remove this check. The original intend was to catch cases where XDP drivers have not been updated to use xdp.frame_sz, but that is not longer a concern (since xdp_init_buff). Running the initial syzkaller repro it was discovered that the contiguous physical memory allocation is used for both xdp paths in tun_get_user(), e.g. tun_build_skb() and tun_alloc_skb(). It was also stated by Jesper Dangaard Brouer <jbrouer@redhat.com> that XDP can work on higher order pages, as long as this is contiguous physical memory (e.g. a page).
Title net: core: remove unnecessary frame_sz check in bpf_xdp_adjust_tail()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-11T19:56:33.077Z

Reserved: 2025-12-24T13:02:52.530Z

Link: CVE-2023-54155

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2025-12-24T13:16:17.510

Modified: 2026-04-15T00:35:42.020

Link: CVE-2023-54155

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-12-24T00:00:00Z

Links: CVE-2023-54155 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses

No weakness.