CVE-2026-43464 - Vulnerability Details

- net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ

Description

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

net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ

XDP multi-buf programs can modify the layout of the XDP buffer when the
program calls bpf_xdp_pull_data() or bpf_xdp_adjust_tail(). The
referenced commit in the fixes tag corrected the assumption in the mlx5
driver that the XDP buffer layout doesn't change during a program
execution. However, this fix introduced another issue: the dropped
fragments still need to be counted on the driver side to avoid page
fragment reference counting issues.

Such issue can be observed with the
test_xdp_native_adjst_tail_shrnk_data selftest when using a payload of
3600 and shrinking by 256 bytes (an upcoming selftest patch): the last
fragment gets released by the XDP code but doesn't get tracked by the
driver. This results in a negative pp_ref_count during page release and
the following splat:

WARNING: include/net/page_pool/helpers.h:297 at mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core], CPU#12: ip/3137
Modules linked in: [...]
CPU: 12 UID: 0 PID: 3137 Comm: ip Not tainted 6.19.0-rc3+ #12 NONE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
RIP: 0010:mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core]
[...]
Call Trace:
<TASK>
mlx5e_dealloc_rx_wqe+0xcb/0x1a0 [mlx5_core]
mlx5e_free_rx_descs+0x7f/0x110 [mlx5_core]
mlx5e_close_rq+0x50/0x60 [mlx5_core]
mlx5e_close_queues+0x36/0x2c0 [mlx5_core]
mlx5e_close_channel+0x1c/0x50 [mlx5_core]
mlx5e_close_channels+0x45/0x80 [mlx5_core]
mlx5e_safe_switch_params+0x1a5/0x230 [mlx5_core]
mlx5e_change_mtu+0xf3/0x2f0 [mlx5_core]
netif_set_mtu_ext+0xf1/0x230
do_setlink.isra.0+0x219/0x1180
rtnl_newlink+0x79f/0xb60
rtnetlink_rcv_msg+0x213/0x3a0
netlink_rcv_skb+0x48/0xf0
netlink_unicast+0x24a/0x350
netlink_sendmsg+0x1ee/0x410
__sock_sendmsg+0x38/0x60
____sys_sendmsg+0x232/0x280
___sys_sendmsg+0x78/0xb0
__sys_sendmsg+0x5f/0xb0
[...]
do_syscall_64+0x57/0xc50

This patch fixes the issue by doing page frag counting on all the
original XDP buffer fragments for all relevant XDP actions (XDP_TX ,
XDP_REDIRECT and XDP_PASS). This is basically reverting to the original
counting before the commit in the fixes tag.

As frag_page is still pointing to the original tail, the nr_frags
parameter to xdp_update_skb_frags_info() needs to be calculated
in a different way to reflect the new nr_frags.

Published: 2026-05-08

Score: 7.0 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

XDP multi-buffer programs can modify the layout of the XDP buffer by pulling data or adjusting the tail. The mlx5e driver incorrectly assumes the layout remains unchanged, and after a recent patch the driver fails to count dropped fragments. This results in an undercount of page fragments, leading to a negative reference count during page release and a kernel crash (splat). The flaw is identified as CWE‑911, an unsafe use of network device interfaces.

Affected Systems

All Linux kernel installations that include the mlx5e network driver before the merge that fixed the fragment counting bug are potentially affected. No specific version ranges are listed; the issue applies to every release containing the vulnerable driver before the patch.

Risk and Exploitability

Because the bug can be triggered by network traffic processed by XDP programs, the attack vector is inferred to be through network packets carrying malicious or malformed data that engage XDP buffer adjustments. The CVSS score is 7.0, and the EPSS score is < 1%; the vulnerability is not listed in CISA's KEV catalog. The result of a kernel panic constitutes a high‑impact denial of service and poses a significant risk to systems that cannot be immediately patched.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`afd5ba577c10639f62e8120df67dc70ea4b61176`	affected	< c74557495efb4bd0adefdfc8678ecdbc82a06da3
`afd5ba577c10639f62e8120df67dc70ea4b61176`	affected	< 03cb50e5b74fce8bf6d92b860371b66253cf0f8d
`afd5ba577c10639f62e8120df67dc70ea4b61176`	affected	< a6413e6f6c9d9bb9833324cb3753582f7bc0f2fa
`72328f25755ee966724f46e3a0e8e59bef2091ba`	affected	—
`0049fd63881505566824e88cfa624638f921c808`	affected	—
`d969645b9b7810289bf3c353ea06957373756b8e`	affected	—

Linux

affected

Version	Status	Constraints
`6.18`	affected	—
`0`	unaffected	< 6.18
`6.18.19`	unaffected	≤ 6.18.*
`6.19.9`	unaffected	≤ 6.19.*
`7.0`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[afd5ba577c10639f62e8120df67dc70ea4b61176,c74557495efb4bd0adefdfc8678ecdbc82a06da3)`	affected	code_commit	—
`[afd5ba577c10639f62e8120df67dc70ea4b61176,03cb50e5b74fce8bf6d92b860371b66253cf0f8d)`	affected	code_commit	—
`[afd5ba577c10639f62e8120df67dc70ea4b61176,a6413e6f6c9d9bb9833324cb3753582f7bc0f2fa)`	affected	code_commit	—
`72328f25755ee966724f46e3a0e8e59bef2091ba`	affected	code_commit	—
`0049fd63881505566824e88cfa624638f921c808`	affected	code_commit	—
`d969645b9b7810289bf3c353ea06957373756b8e`	affected	code_commit	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`6.18`	affected	generic	—
`[0,6.18)`	unaffected	generic	—
`[6.18.19,6.19.0)`	unaffected	semver	—
`[6.19.9,6.20.0)`	unaffected	semver	—
`[7.0,*]`	unaffected	generic	—

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Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

Upgrade the Linux kernel to a release that contains the fix for the mlx5e driver (any kernel after the commit that corrected the fragment counting).
If a kernel upgrade cannot be performed immediately, disable XDP functionality on the affected mlx5e interfaces to avoid the buffer modification scenario that triggers the fault.
Continuously monitor system logs for warnings about page pool reference count abuses or kernel panics; if such events occur, urgently apply a newer kernel or adjust XDP usage.

Generated by OpenCVE AI on May 9, 2026 at 16:21 UTC.

Tracking

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Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00017.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/03cb50e5b74fce8bf6d92b860371b66253cf0f8d
https://git.kernel.org/stable/c/a6413e6f6c9d9bb9833324cb3753582f7bc0f2fa
https://git.kernel.org/stable/c/c74557495efb4bd0adefdfc8678ecdbc82a06da3
https://lore.kernel.org/linux-cve-announce/2026050802-CVE-2026-43464-5c7a@gregkh/T
https://nvd.nist.gov/vuln/detail/CVE-2026-43464
https://www.cve.org/CVERecord?id=CVE-2026-43464

History

Sat, 09 May 2026 14:30:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-399 CWE-416

Sat, 09 May 2026 12:15:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-911
References		https://lore.kernel.org/linux-cve-announce/2026050802-CVE-2026-43464-5c7a@gregkh/T https://nvd.nist.gov/vuln/detail/CVE-2026-43464 https://www.cve.org/CVERecord?id=CVE-2026-43464
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`

Fri, 08 May 2026 19:30:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-399 CWE-416

Fri, 08 May 2026 14:45:00 +0000

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ XDP multi-buf programs can modify the layout of the XDP buffer when the program calls bpf_xdp_pull_data() or bpf_xdp_adjust_tail(). The referenced commit in the fixes tag corrected the assumption in the mlx5 driver that the XDP buffer layout doesn't change during a program execution. However, this fix introduced another issue: the dropped fragments still need to be counted on the driver side to avoid page fragment reference counting issues. Such issue can be observed with the test_xdp_native_adjst_tail_shrnk_data selftest when using a payload of 3600 and shrinking by 256 bytes (an upcoming selftest patch): the last fragment gets released by the XDP code but doesn't get tracked by the driver. This results in a negative pp_ref_count during page release and the following splat: WARNING: include/net/page_pool/helpers.h:297 at mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core], CPU#12: ip/3137 Modules linked in: [...] CPU: 12 UID: 0 PID: 3137 Comm: ip Not tainted 6.19.0-rc3+ #12 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 RIP: 0010:mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core] [...] Call Trace: <TASK> mlx5e_dealloc_rx_wqe+0xcb/0x1a0 [mlx5_core] mlx5e_free_rx_descs+0x7f/0x110 [mlx5_core] mlx5e_close_rq+0x50/0x60 [mlx5_core] mlx5e_close_queues+0x36/0x2c0 [mlx5_core] mlx5e_close_channel+0x1c/0x50 [mlx5_core] mlx5e_close_channels+0x45/0x80 [mlx5_core] mlx5e_safe_switch_params+0x1a5/0x230 [mlx5_core] mlx5e_change_mtu+0xf3/0x2f0 [mlx5_core] netif_set_mtu_ext+0xf1/0x230 do_setlink.isra.0+0x219/0x1180 rtnl_newlink+0x79f/0xb60 rtnetlink_rcv_msg+0x213/0x3a0 netlink_rcv_skb+0x48/0xf0 netlink_unicast+0x24a/0x350 netlink_sendmsg+0x1ee/0x410 __sock_sendmsg+0x38/0x60 ____sys_sendmsg+0x232/0x280 ___sys_sendmsg+0x78/0xb0 __sys_sendmsg+0x5f/0xb0 [...] do_syscall_64+0x57/0xc50 This patch fixes the issue by doing page frag counting on all the original XDP buffer fragments for all relevant XDP actions (XDP_TX , XDP_REDIRECT and XDP_PASS). This is basically reverting to the original counting before the commit in the fixes tag. As frag_page is still pointing to the original tail, the nr_frags parameter to xdp_update_skb_frags_info() needs to be calculated in a different way to reflect the new nr_frags.
Title		net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/03cb50e5b74fce8bf6d92b860371b66253cf0f8d https://git.kernel.org/stable/c/a6413e6f6c9d9bb9833324cb3753582f7bc0f2fa https://git.kernel.org/stable/c/c74557495efb4bd0adefdfc8678ecdbc82a06da3

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-05-08T14:22:26.039Z

Updated: 2026-05-08T14:22:26.039Z

Reserved: 2026-05-01T14:12:56.011Z

Link: CVE-2026-43464

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-05-08T15:16:59.283

Modified: 2026-05-08T15:16:59.283

Link: CVE-2026-43464

Redhat

Severity : Moderate

Publid Date: 2026-05-08T00:00:00Z

Links: CVE-2026-43464 - Bugzilla

OpenCVE Enrichment

Updated: 2026-05-09T16:30:37Z

Weaknesses

CWE-911

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Local

Attack Complexity High

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

Subscriptions

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