CVE-2026-64403: Bluetooth: L2CAP: validate option length before reading conf opt value

highCVSS 7.1CVE-2026-64403

CSIRTS triage

Other

What: A validation issue exists in Bluetooth L2CAP regarding option length before reading configuration option values.
Who is affected: Affected systems using Bluetooth L2CAP.
Urgency: The urgency is unclear due to unknown severity.
Action: Monitor for updates regarding this vulnerability.

AI-assisted analysis generated from the source advisory — verify against the original.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.1
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64403

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-644030.27% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 18% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-64403	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

highCVE-2026-64403: In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: validate…nvd

Recent advisories for Bluetooth

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

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mediumCVE-2026-2411: Zephyr's Bluetooth host declares a GATT characteristic as two consecutive attributes: a Charact…nvd · 2026-08-01
highCVE-2026-10685: The Zephyr Bluetooth GATT client CCC-write response handler gatt_write_ccc_rsp() in subsys/blu…nvd · 2026-07-31
mediumCVE-2026-17986: Insufficient policy enforcement in Bluetooth in Google Chrome prior to 151.0.7922.72 allowed a…nvd · 2026-07-30