# CVE-2026-89583: Bluetooth: eir: Fix OOB read in eir_get_service_data()

> A remote attacker can trigger an out-of-bounds read in the Linux kernel Bluetooth stack to disclose sensitive memory contents via crafted advertising data.

- **Severity:** High 8.1 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/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:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-100524, BELL-CVE-2026-89583, DEBIAN-CVE-2026-89583, GHSA-q3pj-rcr4-5rqx, UBUNTU-CVE-2026-89583

## What is CVE-2026-89583?

CVE-2026-89583 is a high-severity vulnerability in Linux, published on 11 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: eir: Fix OOB read in eir_get_service_data()

eir_get_service_data() walks the advertising data for a Service Data
field with a matching UUID.  On a mismatch it advances:

    eir += dlen;
    eir_len -= dlen;

eir_get_data() reports dlen as the field's data length, but the field
spans dlen + 2 bytes once its length and type bytes count, and more
when non-Service-Data fields were skipped to reach it.  The pointer
lands correctly on the next field.  eir_len does not, and the shortfall
compounds across fields until eir_get_data() reads the length and type
bytes of a "field" past the end of the buffer.

For an ISO broadcast sink that buffer is hcon->le_per_adv_data[], filled
from the periodic advertising reports of a remote broadcaster.  A PA
payload packed with mismatching Service Data fields walks off the array
into the rest of struct hci_conn.  A drifted field that matches the BAA
UUID puts those bytes in iso_pi(sk)->base, where user space reads them
back with getsockopt(BT_ISO_BASE).

Recompute eir_len from the end of the buffer each iteration.

## Which versions are affected by CVE-2026-89583?


## How do I fix CVE-2026-89583?

Apply the vendor's patch.

## Is CVE-2026-89583 being exploited?

There is no known exploitation of CVE-2026-89583 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89583 and fix it if it is affected.

What it is: CVE-2026-89583 is a high-severity vulnerability in Linux, published on 11 Sep 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-2026-89583 in the wild and no public exploit code.

Affected product: Linux. 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-2026-89583/ (Markdown: https://insights.sbomify.com/CVE-2026-89583/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89583
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89583
- OSV: https://osv.dev/vulnerability/CVE-2026-89583

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89583/
Summaries are generated and may contain mistakes; the official description above is the record.