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
Impact:
n/a
Action:
n/a
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
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Advisories
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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.