CVE-2026-98193 in Linux
Summary
by MITRE • 10/06/2026
In the Linux kernel, the following vulnerability has been resolved:
wifi: libipw: reject TKIP frames without a full MIC
libipw_michael_mic_verify() assumes that an skb contains an eight-byte Michael MIC. A short TKIP frame makes the unsigned payload length wrap, causing michael_mic() to read past the skb.
Check that the MIC is present before verifying it, and use the existing MICHAEL_MIC_LEN constant for all MIC lengths in the verifier.
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Analysis
by VulDB Data Team • 10/07/2026
The Linux kernel vulnerability identified within the wifi: libipw subsystem represents a critical memory safety issue rooted in improper input validation during the processing of TKIP frames. The core technical flaw resides in the libipw_michael_mic_verify function, which is responsible for verifying the integrity of wireless network traffic using the Michael Message Integrity Code algorithm. This routine operates under the implicit assumption that every received socket buffer contains a complete eight-byte Michael MIC appended to its payload. When an attacker crafts or manipulates TKIP frames with truncated payloads, this assumption fails catastrophically. Specifically, if the frame is short enough such that subtracting the expected MIC length from the total packet length results in a negative value, the unsigned integer arithmetic causes the calculated payload length to wrap around to a very large positive number. This integer overflow condition leads the michael_mic function to read memory far beyond the boundaries of the allocated socket buffer, resulting in an out-of-bounds read vulnerability that can expose sensitive kernel data or cause system instability depending on what resides at those adjacent memory locations.
From a security architecture perspective, this flaw aligns with CWE-125, which describes Out-of-Bounds Read vulnerabilities where software reads past the end of a buffer due to insufficient boundary checks. The root cause is classified under CWE-190, Integer Overflow or Wraparound, as the arithmetic operation involving packet length and MIC size fails to account for negative results when using unsigned types without proper validation. In terms of adversary tactics, this vulnerability could potentially be leveraged within an ATT&CK framework context related to Initial Access or Defense Evasion if exploited in conjunction with other weaknesses, although its primary impact is often denial of service through kernel panic or information disclosure via memory leakage. The lack of explicit length verification before cryptographic operations allows malicious actors to trigger these conditions remotely by sending specially crafted wireless packets that exploit the parsing logic within the legacy IEEE 802.11b/g driver stack.
The operational impact of this vulnerability extends beyond simple data corruption, as it compromises the integrity and availability of systems relying on affected kernel versions for Wi-Fi connectivity. An attacker capable of injecting or modifying network traffic in range could trigger these malformed packets to cause a denial of service by crashing the host system through an oops or panic condition resulting from invalid memory access. Furthermore, if the out-of-bounds read accesses sensitive kernel structures such as cryptographic keys, authentication tokens, or other process data, it could lead to unauthorized information disclosure. This undermines the fundamental security guarantees provided by TKIP encryption and integrity mechanisms, effectively allowing attackers to bypass intended protections against tampering with wireless communications.
To mitigate this risk, immediate patching of the Linux kernel is required to apply the fix that introduces explicit validation checks before invoking the Michael MIC verification routine. The corrected implementation ensures that the presence of a full eight-byte MIC is verified prior to any cryptographic processing, thereby preventing the integer wraparound scenario. Developers and system administrators should also consider disabling legacy Wi-Fi protocols like TKIP if modern alternatives such as WPA3 or robust AES-CCMP are available, given that TKIP itself contains known weaknesses beyond this specific implementation flaw. Regular auditing of network-facing drivers for similar assumptions about packet structure completeness is recommended to prevent analogous vulnerabilities in other subsystems where cryptographic integrity checks depend on precise buffer boundaries.