CVE-2026-81507: CWE-125: Out-of-bounds Read in espressif esp-idf
Description
An out-of-bounds read vulnerability exists in the Espressif ESP-IDF Bluetooth stack's L2CAP configuration-option processing. This flaw allows a remote unauthenticated Bluetooth BR/EDR peer to send a malformed L2CAP configuration request that triggers the vulnerability. Under certain runtime conditions, this may cause limited adjacent Bluetooth stack memory to be included in an outbound response. The issue affects ESP32-class products using the BlueDroid host stack with Classic Bluetooth enabled. Fixed versions include 5.2.8, 5.3.6, 5.5.5, 6.0.3, and 6.1-rc1.
CVSS v3.1
Score 6.5medium
Affected software
espressif
esp-idf
pkg:github/espressif/esp-idfRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-81507 is an out-of-bounds read vulnerability (CWE-125) in the ESP-IDF BlueDroid L2CAP configuration-option processing code (l2c_main.c and l2c_utils.c). Prior to fixed versions, the code does not consistently validate option lengths against the remaining received packet bytes. A remote unauthenticated BR/EDR Bluetooth peer within radio range can send a malformed L2CAP configuration request that causes an out-of-bounds read. This may result in limited adjacent Bluetooth stack memory being included in an outbound L2CAP Configuration Response. The vulnerability affects ESP32-class products using the BlueDroid host stack with Classic Bluetooth enabled. The issue is fixed in ESP-IDF versions 5.2.8, 5.3.6, 5.5.5, 6.0.3, and 6.1-rc1.
Potential Impact
A remote unauthenticated attacker within Bluetooth radio range can trigger an out-of-bounds read by sending a malformed L2CAP configuration request. This may lead to disclosure of limited adjacent memory from the Bluetooth stack in an outbound response. The CVSS 3.1 base score is 6.5 (medium severity) with high confidentiality impact but no integrity or availability impact.
Mitigation Recommendations
This vulnerability is fixed in ESP-IDF versions 5.2.8, 5.3.6, 5.5.5, 6.0.3, and 6.1-rc1. Users should upgrade to one of these versions or later to remediate the issue. No additional mitigation is indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-26T20:58:58.083Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ace4bf42cdf04f6567ca2ac
Added to database: 10/13/2026, 15:19:16 UTC
Last enriched: 10/13/2026, 15:33:34 UTC
Last updated: 10/13/2026, 15:34:05 UTC
Views: 5
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