VulnerabilityPublished 19 Jul 2026

CVE-2026-64126: Linux kernel · Bluetooth: MGMT: validate Add Extended Advertising Data length

Source GCVE Database

Authoritative record:CVE-2026-64126· High 7.3

Not known to be exploited · CVSS 7.3 High · fixed in f1febe93ef075314615f970a87681d9ab86691d1 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score

7.3High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in f1febe93ef075314615f970a87681d9ab86691d1, d3f7d17960ed50df3a6709c5158caff989c8c905, a143ce77a5292f2c9285137433d879ce71d190a7 +4

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-ffq8-9j34-f4r6

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 12410572833a283ce92fcf9679ca8a2f372097ee, < f1febe93ef075314615f970a87681d9ab86691d1	Fixed in f1febe93ef075314615f970a87681d9ab86691d1
LinuxLinux	Affected ≥ 12410572833a283ce92fcf9679ca8a2f372097ee, < d3f7d17960ed50df3a6709c5158caff989c8c905	Fixed in d3f7d17960ed50df3a6709c5158caff989c8c905
LinuxLinux	Affected ≥ 12410572833a283ce92fcf9679ca8a2f372097ee, < a143ce77a5292f2c9285137433d879ce71d190a7	Fixed in a143ce77a5292f2c9285137433d879ce71d190a7
LinuxLinux	Affected ≥ 12410572833a283ce92fcf9679ca8a2f372097ee, < a6c75a3fad226ccbd8ef9110dee87c92c299f2ab	Fixed in a6c75a3fad226ccbd8ef9110dee87c92c299f2ab
LinuxLinux	Affected ≥ 12410572833a283ce92fcf9679ca8a2f372097ee, < 14b01b9cba04e6ce82825f68fc4c4322fa4ffa43	Fixed in 14b01b9cba04e6ce82825f68fc4c4322fa4ffa43
LinuxLinux	Affected ≥ 12410572833a283ce92fcf9679ca8a2f372097ee, < 0d5104390b445e7bd664ad583837e4c04d892c9d	Fixed in 0d5104390b445e7bd664ad583837e4c04d892c9d

AI-suggested

A fix has been implemented in the Linux kernel to reject malformed Bluetooth MGMT_OP_ADD_EXT_ADV_DATA commands with invalid length fields before parsing the data. Users should apply the official Linux kernel updates that include this fix. Since this is a kernel vulnerability, updating to a patched kernel version is the recommended remediation. No additional mitigations are indicated by the vendor advisory.

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: MGMT: validate Add Extended Advertising Data length MGMT_OP_ADD_EXT_ADV_DATA is registered as a variable-length command, with MGMT_ADD_EXT_ADV_DATA_SIZE as the fixed header size. The handler then uses cp->adv_data_len and cp->scan_rsp_len to validate and copy cp->data, but it never checks that those bytes are part of the mgmt command payload. A short command can therefore make add_ext_adv_data() pass an out-of-bounds pointer into tlv_data_is_valid(). If the bytes beyond the command buffer are addressable, they can also be copied into the advertising instance as scan response data, where the caller can read them back via MGMT_OP_GET_ADV_INSTANCE. The trigger requires CAP_NET_ADMIN in the initial user namespace; KASAN reports an 8-byte slab-out-of-bounds read. Reject commands whose length does not match the fixed header plus both advertising data lengths before parsing cp->data.

Impact

An attacker with CAP_NET_ADMIN privileges in the initial user namespace could exploit this vulnerability to cause an out-of-bounds read in kernel memory. This could lead to information disclosure of kernel memory contents via Bluetooth advertising data. There is no indication of code execution or privilege escalation from the provided data. No known exploits are reported in the wild.

Summary

The Linux kernel's Bluetooth MGMT_OP_ADD_EXT_ADV_DATA command handler did not properly validate that the lengths of advertising and scan response data were within the bounds of the command payload. This allowed a short command to cause an out-of-bounds read in add_ext_adv_data(), passing an invalid pointer to tlv_data_is_valid(). If the out-of-bounds memory is accessible, it could be copied into the advertising instance and later read back by the caller. The vulnerability requires CAP_NET_ADMIN privileges and was detected by KASAN as an 8-byte slab-out-of-bounds read. The fix involves rejecting commands whose length does not match the fixed header plus both advertising data lengths before processing the data.

References

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