Bug 2507253 (CVE-2026-64440)

Summary: CVE-2026-64440 kernel: staging: rtl8723bs: fix OOB write in HT_caps_handler()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's `rtl8723bs` Wi-Fi driver. A remote attacker, by operating a malicious Access Point (AP), can send a specially crafted 802.11 AssocResponse frame. This can trigger an out-of-bounds write vulnerability in the `HT_caps_handler()` function, leading to memory corruption. This memory corruption could allow an attacker to cause a denial of service or potentially execute arbitrary code.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-07-25 10:12:59 UTC 
In the Linux kernel, the following vulnerability has been resolved:

staging: rtl8723bs: fix OOB write in HT_caps_handler()

HT_caps_handler() iterates pIE->length bytes and writes into
HT_caps.u.HT_cap[], which is a fixed 26-byte array (sizeof struct
HT_caps_element). Because pIE->length is a raw u8 from an over-the-air
802.11 AssocResponse frame and is never validated, a malicious AP can
set it up to 255, causing up to 229 bytes of out-of-bounds writes into
adjacent fields of struct mlme_ext_info.

Truncate the iteration count to the size of HT_caps.u.HT_cap using
umin() so that data from a longer-than-expected IE is silently ignored
rather than written out of bounds, preserving interoperability with APs
that pad the element. An early return on oversized IEs was considered
but rejected: it would bypass the pmlmeinfo->HT_caps_enable = 1
assignment that precedes the loop, silently disabling HT mode for APs
that append extra bytes to the HT Capabilities IE.
Comment 1 TEJ RATHI 2026-07-29 06:36:08 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072538-CVE-2026-64440-7b48@gregkh/T