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FKIE_CVE-2026-74336

Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-17 06:19
Severity
Summary
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.
Impacted products
Vendor Product Version

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/ieee80211-s1g.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3abc13ec3ac28c343ad7e7b7496e807b924f0edd",
              "status": "affected",
              "version": "e0c47c6229c25b54440fe1f84a0ff533942290b1",
              "versionType": "git"
            },
            {
              "lessThan": "b224d18b1e5d1cddfc67f63f41d80023b2ec8889",
              "status": "affected",
              "version": "e0c47c6229c25b54440fe1f84a0ff533942290b1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "include/linux/ieee80211-s1g.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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": "CVE-2026-74336",
  "lastModified": "2026-08-17T06:19:28.073",
  "metrics": {},
  "published": "2026-08-15T06:22:34.510",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3abc13ec3ac28c343ad7e7b7496e807b924f0edd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b224d18b1e5d1cddfc67f63f41d80023b2ec8889"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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