CVE-2026-74336
Received Received - Intake

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Vulnerability report for CVE-2026-74336, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-15

Last updated on: 2026-08-15

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: bound S1G TIM PVB walk to the TIM element ieee80211_s1g_check_tim() parses the S1G Partial Virtual Bitmap (PVB) of a received TIM element. The TIM is handed in as the element payload: ieee802_11_parse_elems_full() stores elems->tim = elem->data and elems->tim_len = elem->datalen (net/mac80211/parse.c), so the valid bytes are [tim, tim + tim_len). When walking the encoded blocks the function passes the walker an end sentinel of (const u8 *)tim + tim_len + 2, i.e. two bytes past the end of the element. ieee80211_s1g_find_target_block() loops while (ptr + 1 <= end) and dereferences ptr (and the per-mode ieee80211_s1g_len_*() helpers read *ptr), so it can read up to two bytes beyond the TIM element -- an out-of-bounds read of adjacent skb/heap data when the TIM is the last element in the frame. The +2 appears to account for the element id/len header, but tim already points past that header at the element payload, so the addend is wrong. Pass the correct element end, (const u8 *)tim + tim_len.

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Meta Information

Published
2026-08-15
Last Modified
2026-08-15
Generated
2026-08-15
AI Q&A
2026-08-15
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

CWE
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a vulnerability in the Linux kernel's WiFi subsystem (mac80211) related to handling S1G TIM elements. The function ieee80211_s1g_check_tim() incorrectly calculates the end boundary when parsing the Partial Virtual Bitmap (PVB) in a TIM element, leading to an out-of-bounds read of up to two extra bytes. This happens because it uses an incorrect end sentinel value, causing it to access memory beyond the intended TIM element payload.

Detection Guidance

This vulnerability is specific to the Linux kernel's mac80211 subsystem and involves an out-of-bounds read in the S1G TIM PVB parsing. Detection requires kernel-level inspection for memory corruption or crashes during WiFi frame processing. No direct commands are provided in the context to detect this issue.

Impact Analysis

This vulnerability could allow an attacker within WiFi range to potentially read adjacent memory from a device's kernel memory space. This might lead to information disclosure, crashes, or privilege escalation if exploited. Systems using vulnerable Linux kernel versions with WiFi capabilities are at risk.

Mitigation Strategies

Apply the latest Linux kernel patches that address this issue. Monitor kernel logs for WiFi-related crashes or memory corruption. Disable affected WiFi features if patches are unavailable. Ensure your kernel version is updated to a fixed release.

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