Description
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: validate rx/tx MLME callback frame lengths before access
cfg80211_rx_mlme_mgmt() and cfg80211_tx_mlme_mgmt() call tracepoints
before rejecting frames shorter than the frame-control field. After
that, they only require len >= 2 before dispatching into subtype
handlers that assume their fixed fields are present.
The frames that trip this are not shorter than 2 bytes; they are short
relative to their subtype. mwifiex is a concrete in-tree example on the
length side: mwifiex_process_mgmt_packet() only requires a 4-address
ieee80211_hdr plus the 2-byte firmware length prefix before handing the
frame to cfg80211_rx_mlme_mgmt(). After stripping the length prefix and
removing addr4, pkt_len can be exactly 24: a bare 3-address management
header with no reason-code body. The existing WARN_ON(len < 2) does not
fire on such a frame, and cfg80211_process_deauth() then reads
u.deauth.reason_code as a two-byte access starting at offset 24,
immediately past the 24-byte buffer.
Add a frame-control length gate, then validate each subtype's minimum
frame size in an if/else-if chain that mirrors the dispatch logic. Trace
only after the frame is known to be well-formed.
Side effects of this change:
- The WARN_ON(len < 2) is dropped. It only guarded the frame_control
read, never the subtype fixed fields, and it does not fire on the
frames that actually trigger the out-of-bounds read (which are >= 2).
The len >= 2 check is kept as the guard before dereferencing
frame_control, but without the warning: these are exported callbacks
and a malformed frame from a driver should be dropped silently rather
than backtraced.
- cfg80211_tx_mlme_mgmt() previously routed every non-deauth subtype
through disassociation handling; it now silently ignores unrecognised
subtypes.
wifi: cfg80211: validate rx/tx MLME callback frame lengths before access
cfg80211_rx_mlme_mgmt() and cfg80211_tx_mlme_mgmt() call tracepoints
before rejecting frames shorter than the frame-control field. After
that, they only require len >= 2 before dispatching into subtype
handlers that assume their fixed fields are present.
The frames that trip this are not shorter than 2 bytes; they are short
relative to their subtype. mwifiex is a concrete in-tree example on the
length side: mwifiex_process_mgmt_packet() only requires a 4-address
ieee80211_hdr plus the 2-byte firmware length prefix before handing the
frame to cfg80211_rx_mlme_mgmt(). After stripping the length prefix and
removing addr4, pkt_len can be exactly 24: a bare 3-address management
header with no reason-code body. The existing WARN_ON(len < 2) does not
fire on such a frame, and cfg80211_process_deauth() then reads
u.deauth.reason_code as a two-byte access starting at offset 24,
immediately past the 24-byte buffer.
Add a frame-control length gate, then validate each subtype's minimum
frame size in an if/else-if chain that mirrors the dispatch logic. Trace
only after the frame is known to be well-formed.
Side effects of this change:
- The WARN_ON(len < 2) is dropped. It only guarded the frame_control
read, never the subtype fixed fields, and it does not fire on the
frames that actually trigger the out-of-bounds read (which are >= 2).
The len >= 2 check is kept as the guard before dereferencing
frame_control, but without the warning: these are exported callbacks
and a malformed frame from a driver should be dropped silently rather
than backtraced.
- cfg80211_tx_mlme_mgmt() previously routed every non-deauth subtype
through disassociation handling; it now silently ignores unrecognised
subtypes.
Published:
2026-09-24
Score:
n/a
EPSS:
n/a
KEV:
No
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
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 | Linux | unaffected |
|
||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
Advisories
No advisories yet.
References
History
Thu, 24 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: wifi: cfg80211: validate rx/tx MLME callback frame lengths before access cfg80211_rx_mlme_mgmt() and cfg80211_tx_mlme_mgmt() call tracepoints before rejecting frames shorter than the frame-control field. After that, they only require len >= 2 before dispatching into subtype handlers that assume their fixed fields are present. The frames that trip this are not shorter than 2 bytes; they are short relative to their subtype. mwifiex is a concrete in-tree example on the length side: mwifiex_process_mgmt_packet() only requires a 4-address ieee80211_hdr plus the 2-byte firmware length prefix before handing the frame to cfg80211_rx_mlme_mgmt(). After stripping the length prefix and removing addr4, pkt_len can be exactly 24: a bare 3-address management header with no reason-code body. The existing WARN_ON(len < 2) does not fire on such a frame, and cfg80211_process_deauth() then reads u.deauth.reason_code as a two-byte access starting at offset 24, immediately past the 24-byte buffer. Add a frame-control length gate, then validate each subtype's minimum frame size in an if/else-if chain that mirrors the dispatch logic. Trace only after the frame is known to be well-formed. Side effects of this change: - The WARN_ON(len < 2) is dropped. It only guarded the frame_control read, never the subtype fixed fields, and it does not fire on the frames that actually trigger the out-of-bounds read (which are >= 2). The len >= 2 check is kept as the guard before dereferencing frame_control, but without the warning: these are exported callbacks and a malformed frame from a driver should be dropped silently rather than backtraced. - cfg80211_tx_mlme_mgmt() previously routed every non-deauth subtype through disassociation handling; it now silently ignores unrecognised subtypes. | |
| Title | wifi: cfg80211: validate rx/tx MLME callback frame lengths before access | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-24T16:02:39.248Z
Reserved: 2026-09-18T17:59:28.790Z
Link: CVE-2026-93805
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-24T17:17:13.460
Modified: 2026-09-24T17:17:13.460
Link: CVE-2026-93805
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.