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Bluetooth: Semi-Arbitrary ability to make the BLE Target send disconnection requests

High
ceolin published GHSA-hcc8-3qr7-c9m8 Sep 19, 2025

Package

zehyr (zephyr)

Affected versions

<= 4.1

Patched versions

None

Description

A vulnerability was identified in the handling of Bluetooth Low Energy (BLE) fixed channels (such as SMP or ATT). Specifically, an attacker could exploit a flaw that causes the BLE target (i.e., the device under attack) to attempt to disconnect a fixed channel, which is not allowed per the Bluetooth specification. This leads to undefined behavior, including potential assertion failures, crashes, or memory corruption, depending on the BLE stack implementation.

  1. In the function le_credits (subsys/bluetooth/host/l2cap.c:2143), which parses the “L2CAP Flow Control Credit Indication” request.
  2. When sending two requests for example (22 credits increase, and 65535 credits increase), the code correctly evaluate the an overflows occurs and send disconnection request.
  3. By creating a disconnection request it “allocates” an identifier associated with the request. This identifier points the channel which credits increase were requested for.
  4. By allocating an identifier the code becomes vulnerable to responses (as it sent a request) as will be seen later.
  5. The code does not check that the CID is 0x05 (LE SIGNAL CHANNEL) or any other of the fixed channels (SMP,
    ATT...) Leading to the BLE target attempting to disconnect a “fixed channel”.

Impact

Remote crash or denial of service via malformed BLE traffic.

Patches

For more information

If you have any questions or comments about this advisory:

embargo: 2025-09-05

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

CVE ID

CVE-2025-10456

Weaknesses

Integer Overflow or Wraparound

The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. Learn more on MITRE.