# CVE-2026-53255: Bluetooth: MGMT: validate advertising TLV before type checks

> A local attacker can trigger an out-of-bounds read in the Linux kernel Bluetooth subsystem via malformed advertising data, causing a crash or information leak.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Jun 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-90680, BELL-CVE-2026-53255, DEBIAN-CVE-2026-53255, GHSA-hxxh-4jr7-w99w, ROOT-OS-DEBIAN-11-CVE-2026-53255, ROOT-OS-DEBIAN-12-CVE-2026-53255, ROOT-OS-UBUNTU-2204-CVE-2026-53255, ROOT-OS-UBUNTU-2404-CVE-2026-53255, UBUNTU-CVE-2026-53255

## What is CVE-2026-53255?

CVE-2026-53255 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Jun 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: MGMT: validate advertising TLV before type checks

tlv_data_is_valid() reads each advertising data field length from
data[i], then inspects data[i + 1] for managed EIR types before
checking that the current field still fits inside the supplied buffer.

A malformed field whose length byte is the last byte of the buffer can
therefore make the parser read one byte past the advertising data.

KASAN reported the following when a malformed MGMT_OP_ADD_ADVERTISING
request reached that path:

  BUG: KASAN: vmalloc-out-of-bounds in tlv_data_is_valid()
  Read of size 1
  Call trace:
    tlv_data_is_valid()
    add_advertising()
    hci_mgmt_cmd()
    hci_sock_sendmsg()

Move the existing element-length check before any type-octet inspection
so each non-empty element is proven to contain its type byte before the
parser looks at data[i + 1].

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-53255?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53255?

Apply the vendor's patch.

## Is CVE-2026-53255 being exploited?

There is no known exploitation of CVE-2026-53255 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53255 and fix it if it is affected.

What it is: CVE-2026-53255 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 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-2026-53255 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-53255/ (Markdown: https://insights.sbomify.com/CVE-2026-53255/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53255
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53255
- OSV: https://osv.dev/vulnerability/CVE-2026-53255

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53255/
Summaries are generated and may contain mistakes; the official description above is the record.