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VulnerabilityPublished Updated

CVE-2026-64440: Linux kernel · staging: rtl8723bs: fix OOB write in HT_caps_handler()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.1 High · fixed in f8001e1a516ba3b495728c65b61f799cbfad6bd0 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
8.1High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in f8001e1a516ba3b495728c65b61f799cbfad6bd0, bb3b942da4123b55d1cacf19d1a7d5ba15dbf83a, 918537a0fbed85aab61fa28ad75e6279070610c9 +4
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 554c0a3abf216c991c5ebddcdb2c08689ecd290b, < f8001e1a516ba3b495728c65b61f799cbfad6bd0
Fixed in
  • f8001e1a516ba3b495728c65b61f799cbfad6bd0
LinuxLinuxAffected
  • ≥ 554c0a3abf216c991c5ebddcdb2c08689ecd290b, < bb3b942da4123b55d1cacf19d1a7d5ba15dbf83a
Fixed in
  • bb3b942da4123b55d1cacf19d1a7d5ba15dbf83a
LinuxLinuxAffected
  • ≥ 554c0a3abf216c991c5ebddcdb2c08689ecd290b, < 918537a0fbed85aab61fa28ad75e6279070610c9
Fixed in
  • 918537a0fbed85aab61fa28ad75e6279070610c9
LinuxLinuxAffected
  • ≥ 554c0a3abf216c991c5ebddcdb2c08689ecd290b, < 225b6d3fc7e99ac3d20b6c861d1e47d24e7ea31d
Fixed in
  • 225b6d3fc7e99ac3d20b6c861d1e47d24e7ea31d
LinuxLinuxAffected
  • ≥ 554c0a3abf216c991c5ebddcdb2c08689ecd290b, < 37f642d47c3648a707df3ceb092eee1adffbfd28
Fixed in
  • 37f642d47c3648a707df3ceb092eee1adffbfd28
LinuxLinuxAffected
  • ≥ 554c0a3abf216c991c5ebddcdb2c08689ecd290b, < 8c872b47c7fc32e95e0da1db7512388794adcd69
Fixed in
  • 8c872b47c7fc32e95e0da1db7512388794adcd69

Description

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.

References

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