# CVE-2026-10658: Out-of-bounds access in Bluetooth ISO receive (`bt_iso_recv`) due to missing SDU-header length validation

> A malicious Bluetooth peer can trigger out-of-bounds reads and writes in Zephyr RTOS ISO receive handling, potentially leading to code execution or crashes.

- **Severity:** High 7.1 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 22 Jun 2026
- **Updated:** 15 Oct 2026
- **Also known as:** GHSA-26g8-rmpf-j6cw, UBUNTU-CVE-2026-10658

## What is CVE-2026-10658?

CVE-2026-10658 is a high-severity memory corruption vulnerability in Zephyrproject Zephyr, published on 22 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

bt_iso_recv() in subsys/bluetooth/host/iso.c pulled the ISO SDU header (4 bytes) or, when the timestamp flag is set, the timestamped SDU header (8 bytes) from the inbound HCI ISO Data buffer via net_buf_pull_mem() without first checking buf->len. The upstream hci_iso() handler enforces buf->len == the controller-declared ISO Data_Load length, so a malicious or buggy controller / adjacent BLE peer on an established CIS/BIS can present a first-fragment (BT_ISO_START) or single (BT_ISO_SINGLE) PDU shorter than the SDU header. Because net_buf_simple_pull_mem only guards length with __ASSERT_NO_MSG (compiled out when CONFIG_ASSERT is disabled, the production default), the pull underflows buf->len (uint16_t, e.g. 0 - 8 = 0xFFF8) and advances buf->data past valid data: the subsequent reads of hdr->slen and hdr->sn are out-of-bounds reads of adjacent pool memory. For the multi-fragment (START) case the corrupted buffer is retained as iso->rx, and a following CONT/END fragment's net_buf_tailroom() guard underflows to a near-SIZE_MAX value, defeating the bounds check and causing net_buf_add_mem() to memcpy attacker-supplied fragment data far past the RX pool buffer (out-of-bounds write). The flaw affects ISO receive builds (CONFIG_BT_ISO_RX, selected by the default-off LE Audio options BT_ISO_PERIPHERAL/BT_ISO_CENTRAL/BT_ISO_SYNC_RECEIVER) and has existed since the ISO subsystem was introduced (v2.6.0) through v4.4.0. The fix adds explicit buf->len < sizeof(ts_hdr) and buf->len < sizeof(hdr) checks that drop the buffer before pulling.

Weakness: CWE-125 (Out-of-bounds Read), CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-10658?

It affects 1 product.


Products: Zephyrproject Zephyr.

## How do I fix CVE-2026-10658?

No fix has been published for CVE-2026-10658 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-10658 being exploited?

There is no known exploitation of CVE-2026-10658 in the wild and no public exploit code.

## Other vulnerabilities in Zephyrproject Zephyr

- [CVE-2026-5067](https://insights.sbomify.com/CVE-2026-5067/): Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key (critical 9.8)
- [CVE-2022-3806](https://insights.sbomify.com/CVE-2022-3806/): Bluetooth HCI Error Handling Double Free (critical 9.8)
- [CVE-2017-14199](https://insights.sbomify.com/CVE-2017-14199/): Memory corruption in getaddrinfo (critical 9.8)
- [CVE-2018-1000800](https://insights.sbomify.com/CVE-2018-1000800/): Null dereference in n/a (critical 9.8)
- [CVE-2021-3329](https://insights.sbomify.com/CVE-2021-3329/): DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer (critical 9.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-10658 and fix it if it is affected.

What it is: CVE-2026-10658 is a high-severity memory corruption vulnerability in Zephyrproject Zephyr, published on 22 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-10658 in the wild and no public exploit code.

Affected product: Zephyrproject Zephyr. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-10658/ (Markdown: https://insights.sbomify.com/CVE-2026-10658/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-10658
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-10658
- OSV: https://osv.dev/vulnerability/CVE-2026-10658

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-10658/
Summaries are generated and may contain mistakes; the official description above is the record.