Bug 2516755 (CVE-2026-74336) - CVE-2026-74336 kernel: wifi: mac80211: bound S1G TIM PVB walk to the TIM element
Summary: CVE-2026-74336 kernel: wifi: mac80211: bound S1G TIM PVB walk to the TIM element
Keywords:
Status: NEW
Alias: CVE-2026-74336
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-15 06:31 UTC by OSIDB Bzimport
Modified: 2026-08-20 17:55 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-08-15 06:31:49 UTC
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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