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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No vendor fix or workaround currently provided.
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Sat, 15 Aug 2026 17:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-119 CWE-125 |
Sat, 15 Aug 2026 06:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | wifi: mac80211: bound S1G TIM PVB walk to the TIM element | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-15T05:58:27.799Z
Reserved: 2026-08-15T05:44:03.885Z
Link: CVE-2026-74336
No data.
Status : Received
Published: 2026-08-15T06:22:34.510
Modified: 2026-08-15T06:22:34.510
Link: CVE-2026-74336
No data.
OpenCVE Enrichment
Updated: 2026-08-15T16:45:10Z