CVE-2026-98810

wifi: mac80211: fix slab-out-of-bounds read in ieee80211_monitor_select_queue()

Published Oct 18, 2026 CVSS 3.1 · 6.1 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

wifi: mac80211: fix slab-out-of-bounds read in ieee80211_monitor_select_queue()

ieee80211_monitor_select_queue() validates the skb length using skb->len
before dereferencing pointers into skb->data to access the 802.11 header.
However, skb->len includes data in both the linear head buffer and
non-linear fragments/pages. When AF_PACKET sends a packet large enough to
become non-linear, the 802.11 header at skb->data + len_rthdr may extend
past the linear head buffer even though skb->len appears sufficient.

This leads to a slab-out-of-bounds read when accessing hdr->frame_control,
as the kernel reads beyond the allocated skb head buffer:

BUG: KASAN: slab-out-of-bounds in ieee80211_monitor_select_queue+0x1ed/0x220

syzbot has hit the same issues.

Fix this by checking skb_headlen(skb) (which gives the length of the
linear data region) instead of skb->len before dereferencing skb->data
pointers. This ensures the required bytes are actually present in the
linear portion of the skb.

Apply the same fix to ieee80211_validate_radiotap_len() which has the
same class of bug: it uses skb->len to validate accesses to skb->data,
and to the corresponding checks in ieee80211_monitor_start_xmit(): for
drivers advertising NETIF_F_SG the skb is not linearized before
ndo_start_xmit, so the 802.11 header can be read past the linear
buffer there as well.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-9018-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-9018-2 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
History
Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H'}

threat_severity

Moderate

Type Values Removed Values Added
Weaknesses CWE-125
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: fix slab-out-of-bounds read in ieee80211_monitor_select_queue() ieee80211_monitor_select_queue() validates the skb length using skb->len before dereferencing pointers into skb->data to access the 802.11 header. However, skb->len includes data in both the linear head buffer and non-linear fragments/pages. When AF_PACKET sends a packet large enough to become non-linear, the 802.11 header at skb->data + len_rthdr may extend past the linear head buffer even though skb->len appears sufficient. This leads to a slab-out-of-bounds read when accessing hdr->frame_control, as the kernel reads beyond the allocated skb head buffer: BUG: KASAN: slab-out-of-bounds in ieee80211_monitor_select_queue+0x1ed/0x220 syzbot has hit the same issues. Fix this by checking skb_headlen(skb) (which gives the length of the linear data region) instead of skb->len before dereferencing skb->data pointers. This ensures the required bytes are actually present in the linear portion of the skb. Apply the same fix to ieee80211_validate_radiotap_len() which has the same class of bug: it uses skb->len to validate accesses to skb->data, and to the corresponding checks in ieee80211_monitor_start_xmit(): for drivers advertising NETIF_F_SG the skb is not linearized before ndo_start_xmit, so the 802.11 header can be read past the linear buffer there as well.
Title wifi: mac80211: fix slab-out-of-bounds read in ieee80211_monitor_select_queue()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 9:26 AM
Reserved
Sep 25, 2026, 10:25 AM
Status
Received
Published
Oct 18, 2026, 4:17 PM
Modified
Oct 19, 2026, 10:19 AM
Severity
Moderate
Public date
Oct 18, 2026, 12:00 AM