Vulnerability Overview
CVE ID: CVE-2026-23152
Component: Linux Kernel – mac80211 (IEEE 802.11 wireless stack)
Vulnerability Type: Out-of-Bounds Read / Memory Corruption
CWE: CWE-125 (Out-of-Bounds Read)
Attack Vector: Adjacent (Wireless – radio proximity required)
Privileges Required: None
User Interaction: Not required
Scope: Unchanged
Impact: Denial of Service, Potential Information Disclosure
Severity: High
Technical Description
A flaw was identified in the Linux kernel’s mac80211 subsystem, specifically in the handling of the TID-to-Link Mapping (TTLM) element within IEEE 802.11 management frames. The issue occurs during parsing of Multi-Link Operation (MLO) related information elements.
Under certain conditions, when a TTLM element is transmitted using the default link mapping, a specific optional byte (link mapping presence indicator) is omitted as per the 802.11 specification. However, the vulnerable code path in net/mac80211/mlme.c attempted to read this byte unconditionally.
As a result, a one-byte out-of-bounds read occurred when processing crafted wireless management frames. This led to reading memory beyond the allocated buffer boundary.
While the read size is small, in kernel space even minimal boundary violations are significant. Depending on memory layout and runtime conditions, this could result in:
- Kernel crash (Oops / panic)
- Slab memory corruption side-effects
- KASAN out-of-bounds detection
- Potential leakage of adjacent memory
- Unstable wireless stack behavior
The vulnerability is triggered during Wi-Fi frame processing, before authentication or association is completed, making it reachable by a nearby attacker within radio range.
Affected Component Details
- File:
net/mac80211/mlme.c - Functionality: TTLM element decoding logic
- Subsystem: mac80211 wireless stack
- Context: Multi-Link Operation (802.11be / Wi-Fi 7 related handling)
The parsing logic failed to properly validate element length before dereferencing the link mapping presence byte.
Root Cause
The control field of the TTLM element determines whether additional mapping bytes follow. The vulnerable implementation did not validate this condition properly and assumed the presence of the mapping byte even when the element was in default format.
Improper bounds validation allowed:
buffer[offset + 1]
to be accessed without confirming that the element length was sufficient.
This resulted in an out-of-bounds read of adjacent kernel memory.
Exploitation Scenario
This vulnerability is exploitable only via wireless proximity.
An attacker would:
- Operate within Wi-Fi radio range of a vulnerable system.
- Craft a malicious IEEE 802.11 management frame.
- Insert a TTLM element indicating default mapping.
- Manipulate the element length field to exclude the link mapping byte.
- Transmit the frame repeatedly to trigger parsing.
Because the vulnerability exists in frame parsing logic, it may be triggered before full authentication, depending on device state.
No local system access is required.
Proof of Concept Status
At the time of writing:
- No publicly weaponized exploit kit is available.
- No widely distributed PoC repository contains active exploit code.
- The upstream kernel patch clearly demonstrates the vulnerable logic and correction.
For educational research only, a PoC would involve:
- A Wi-Fi adapter capable of monitor mode and injection.
- Frame crafting using tools such as Scapy with raw 802.11 management frames.
- Injection of malformed TTLM elements.
- Monitoring kernel logs for crash or KASAN output.
This should only be performed in a controlled lab environment.
Impact Assessment
1. Denial of Service
Repeated malformed frames could cause:
- Kernel panic
- mac80211 crash
- Wireless subsystem restart
- System instability
2. Information Disclosure
Although the bug is an out-of-bounds read, controlled data exfiltration would be complex due to:
- Kernel memory protections
- KASLR
- SMEP/SMAP
- Modern slab hardening
No confirmed data leakage cases have been documented.
3. Remote Code Execution
Standalone exploitation for RCE is considered unlikely. However, in theory, kernel memory corruption primitives may contribute to multi-stage exploitation chains.
Detection Strategy
1. Kernel Log Monitoring
Monitor for:
- mac80211 warnings
- ieee80211 parsing errors
- TTLM references
- Out-of-bounds messages
- KASAN slab reports
- Kernel Oops / panic traces
Linux Log Query (journalctl)
journalctl -k | egrep -i "mac80211|ieee80211|TTLM|out-of-bounds|KASAN|Oops"
Log File Monitoring
grep -Ei "mac80211|ieee80211|TTLM|KASAN|BUG|Oops" /var/log/kern.log
2. Splunk Detection Query
index=linux_logs sourcetype=kernel
("mac80211" OR "ieee80211" OR "TTLM" OR "out-of-bounds" OR "KASAN")
| stats count by host, message
3. Elastic / Kibana Query
event.dataset: "system.syslog" AND
(message: "mac80211" OR message: "TTLM" OR message: "ieee80211" OR message: "out-of-bounds")
4. Wireless Monitoring
In monitor mode, inspect 802.11 management frames:
Example tshark filter:
tshark -i wlan0mon -Y "wlan.fc.type_subtype == 0x00" -V | grep -i TTLM
If malformed TTLM elements with inconsistent lengths are observed, further investigation is recommended.
Wireless IDS systems (Kismet, custom Zeek scripts with 802.11 support) can be configured to flag malformed information element lengths.
Indicators of Compromise
- Sudden wireless interface resets
- Kernel panic referencing mac80211
- Repeated slab-out-of-bounds messages
- KASAN invalid read reports
- Unexpected reboot after wireless activity
Mitigation and Remediation
Immediate Actions
- Update kernel to patched version.
- Restrict wireless connectivity on critical systems.
- Disable Wi-Fi on servers where unnecessary.
- Increase monitoring of kernel logs.
Long-Term Controls
- Enable KASAN in test environments.
- Ensure automatic kernel patch management.
- Use wireless intrusion detection systems.
- Segment high-value systems from open Wi-Fi networks.
Official Patch
The vulnerability has been fixed upstream in the Linux kernel.
Official patch commit:
https://git.kernel.org/stable/c/1eab33aa63c993685dd341e03bd5b267dd7403fa
It is strongly recommended that distributions be updated through official vendor repositories to ensure proper backporting and compatibility.
Risk Rating Summary
| Factor | Assessment |
|---|---|
| Exploit Complexity | Medium |
| Attack Vector | Adjacent (Wireless) |
| Privileges Required | None |
| Availability of Exploit | No public exploit |
| Operational Impact | High (DoS potential) |
| Likelihood in Enterprise | Moderate (wireless environments) |
Final Takeaway
CVE-2026-23152 represents a classic kernel parsing flaw in wireless frame handling. Although exploitation requires physical proximity, the fact that it resides in kernel space elevates its importance. Immediate patching is strongly recommended in environments where wireless networking is enabled.
The vulnerability does not currently appear to be under active exploitation, but given the simplicity of the flaw and availability of patch diff details, defensive action should not be delayed.
