Linux Kernel up to 7.2-rc2 rtl8723bs HT_caps_handler out-of-bounds write

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k3.15+

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2-rc2. It has been rated as very critical. Impacted is the function HT_caps_handler of the component rtl8723bs. The manipulation leads to out-of-bounds write. This vulnerability is documented as CVE-2026-64440. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2-rc2. It has been rated as very critical. This issue affects the function HT_caps_handler of the component rtl8723bs. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-64440 since 07/19/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/25/2026).

Upgrading to version 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4 or 7.2-rc3 eliminates this vulnerability. Applying the patch 37f642d47c3648a707df3ceb092eee1adffbfd28/8c872b47c7fc32e95e0da1db7512388794adcd69/bb3b942da4123b55d1cacf19d1a7d5ba15dbf83a/918537a0fbed85aab61fa28ad75e6279070610c9/6f91621fc45025ad3c0be796b70e6e4cee22fc69/225b6d3fc7e99ac3d20b6c861d1e47d24e7ea31d/f8001e1a516ba3b495728c65b61f799cbfad6bd0 is able to eliminate this problem.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.15.212/6.1.178/6.6.145/6.12.96/6.18.39/7.1.4/7.2-rc3
Patch: 37f642d47c3648a707df3ceb092eee1adffbfd28/8c872b47c7fc32e95e0da1db7512388794adcd69/bb3b942da4123b55d1cacf19d1a7d5ba15dbf83a/918537a0fbed85aab61fa28ad75e6279070610c9/6f91621fc45025ad3c0be796b70e6e4cee22fc69/225b6d3fc7e99ac3d20b6c861d1e47d24e7ea31d/f8001e1a516ba3b495728c65b61f799cbfad6bd0

Timelineinfo

07/19/2026 CVE reserved
07/25/2026 +6 days Advisory disclosed
07/25/2026 +0 days VulDB entry created
07/25/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64440 (🔒)
GCVE (CVE): GCVE-0-2026-64440
GCVE (VulDB): GCVE-100-383201

Entryinfo

Created: 07/25/2026 18:26
Changes: 07/25/2026 18:26 (59)
Complete: 🔍
Cache ID: 216::103

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