GHSA-4QQ5-4VGC-W78G
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-15 06:32In 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.
{
"affected": [],
"aliases": [
"CVE-2026-74336"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:22:34Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: mac80211: bound S1G TIM PVB walk to the TIM element\n\nieee80211_s1g_check_tim() parses the S1G Partial Virtual Bitmap (PVB) of a\nreceived TIM element. The TIM is handed in as the element payload:\nieee802_11_parse_elems_full() stores elems-\u003etim = elem-\u003edata and\nelems-\u003etim_len = elem-\u003edatalen (net/mac80211/parse.c), so the valid bytes\nare [tim, tim + tim_len).\n\nWhen walking the encoded blocks the function passes the walker an end\nsentinel of (const u8 *)tim + tim_len + 2, i.e. two bytes past the end of\nthe element. ieee80211_s1g_find_target_block() loops while (ptr + 1 \u003c= end)\nand dereferences ptr (and the per-mode ieee80211_s1g_len_*() helpers read\n*ptr), so it can read up to two bytes beyond the TIM element -- an\nout-of-bounds read of adjacent skb/heap data when the TIM is the last\nelement in the frame. The +2 appears to account for the element id/len\nheader, but tim already points past that header at the element payload, so\nthe addend is wrong.\n\nPass the correct element end, (const u8 *)tim + tim_len.",
"id": "GHSA-4qq5-4vgc-w78g",
"modified": "2026-08-15T06:32:30Z",
"published": "2026-08-15T06:32:30Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74336"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3abc13ec3ac28c343ad7e7b7496e807b924f0edd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b224d18b1e5d1cddfc67f63f41d80023b2ec8889"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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Nomenclature
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.