# CVE-2026-10660 — zephyrproject zephyr

> As of 2026-07-11, CVE-2026-10660 is a MEDIUM-severity vulnerability in zephyrproject zephyr, CVSS v3.1 6.4, EPSS 0.1% (5.4th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-10660 as of 2026-07-11; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-07-11

## What is CVE-2026-10660?

The Bluetooth BAP Broadcast Assistant GATT client in subsys/bluetooth/audio/bap_broadcast_assistant.c reassembled remote Broadcast Receive State data into a single file-static net_buf_simple (att_buf, BT_ATT_MAX_ATTRIBUTE_LEN = 512 bytes) shared by all connection instances, while the BUSY flag, long-read handle, and reset/offset state were per-connection. When the device acts as a Broadcast Assistant connected to multiple Scan Delegator peripherals, notification and long-read callbacks from different connections interleave on the shared buffer: the append in notify_handler (net_buf_simple_add_mem at the not-busy branch) performs no tailroom check, so receive-state notifications from two or more delegators accumulate on the same 512-byte buffer and, with a sufficiently large configured ATT MTU (BT_L2CAP_TX_MTU up to 2000) and two-to-three concurrent connections, write past the buffer into adjacent .bss (net_buf_simple_add only asserts in debug builds). Even below the overflow threshold, one connection's net_buf_simple_reset zeroes the shared length while another connection's reassembly and GATT read offset are in flight, mixing one peer's data into another's parse. A malicious or compromised Scan Delegator (or two colluding peers) over BLE can trigger this, causing out-of-bounds writes (memory corruption / denial of service) and cross-connection data corruption. The fix moves the buffer into the per-connection instance struct so each connection reassembles into its own buffer. Affects Zephyr releases shipping the Broadcast Assistant with the shared buffer, including v4.4.0 and earlier.

The record classifies CVE-2026-10660 under weakness class [CWE-787](https://intel.threadlinqs.com/cwe/CWE-787). Its CVSS v3 base vector states that the flaw is reachable from an adjacent network, needs no prior authentication, needs no user interaction, and has high impact on availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 86 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 6.4 — MEDIUM (`CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H`)
- **EPSS (FIRST):** 0.1% probability of exploitation in the next 30 days, higher than 5.4% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 3.4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-11

## Is CVE-2026-10660 being exploited?

It currently carries a trending score of 31 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [zephyrproject](https://intel.threadlinqs.com/vendors/zephyrproject): zephyr

## How to fix CVE-2026-10660

No vendor patch reference has been recorded for CVE-2026-10660 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-10660

No threat campaign in the Threadlinqs corpus currently references CVE-2026-10660, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on 2026-07-12.

**Vendor advisory and patch**

- [github.com — patch](https://github.com/zephyrproject-rtos/zephyr/commit/0cd61589ff820b6a585c73cb36f1e14b043a2795)

**Other references**

- [github.com](https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-73c7-3rh7-v5p9)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-10660
Full detection coverage and IOCs for threats exploiting CVE-2026-10660 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp