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Linux KernelOperating system · Linux

CVE-2026-53254

HIGH · 8.1 CVSS v3.1 Published 2026-06-25
Fix available
A fix is available. Upgrade to 5.15.210 / 6.1.176 or later.
See remediation →
86/100
Remediation priority · High
No privileges Zero-click Patch available 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: validate skb length in MCC handlers The RFCOMM MCC handlers cast skb->data to protocol-specific structs without validating skb->len first. A malicious remote device can send truncated MCC frames and trigger out-of-bounds reads in these handlers. Fix this by using skb_pull_data() to validate and access the required data before dereferencing it. rfcomm_recv_rpn() requires special handling since ETSI TS 07.10 allows 1-byte RPN requests. Handle this by validating only the DLCI byte first, and validating the full struct only when len > 1.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Linux kernel's Bluetooth RFCOMM implementation has an out-of-bounds read vulnerability in MCC (Multiplexer Control Command) handlers. These handlers cast skb->data to protocol-specific structs without validating skb->len first, allowing a malicious remote device to send truncated MCC frames and trigger out-of-bounds reads. The fix requires using skb_pull_data() to validate and access required data before dereferencing, with special handling for rfcomm_recv_rpn() since ETSI TS 07.10 allows 1-byte RPN requests.

MitigationApply the kernel patch that implements skb_pull_data() validation in RFCOMM MCC handlers and update to a kernel version containing this fix.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 2.6.12.1, < 5.15.210>= 5.16, < 6.1.176>= 6.2, < 6.6.143>= 6.7, < 6.12.94>= 6.13, < 6.18.36>= 6.19, < 7.0.13= 2.6.12= 7.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine running kernel version
    Run `uname -r` or `cat /proc/version` to get the exact kernel version string
    Affected if The kernel version falls within any of these ranges: >= 2.6.12.1 and < 5.15.210; >= 5.16 and < 6.1.176; >= 6.2 and < 6.6.143; >= 6.7 and < 6.12.94; >= 6.13 and < 6.18.36; >= 6.19 and < 7.0.13; equals 2.6.12; or equals 7.1
  2. Verify if Bluetooth RFCOMM is enabled
    Check if the rfcomm kernel module is loaded with `lsmod | grep rfcomm`, or check for RFCOMM device nodes with `ls -la /dev/rfcomm*`
    Affected if RFCOMM module is loaded or /dev/rfcomm* device nodes exist, meaning the Bluetooth RFCOMM stack is active and could receive malicious MCC frames
  3. Check for active Bluetooth interfaces
    Run `hciconfig -a` or `bluetoothctl list` to enumerate configured Bluetooth adapters
    Affected if Any Bluetooth adapter is configured and powered on, as remote attackers would need an active Bluetooth connection to send truncated MCC frames

If the kernel version is within the affected ranges AND Bluetooth RFCOMM is actively enabled with a configured adapter, the system is potentially vulnerable to out-of-bounds reads from malicious truncated MCC frames.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.15.210 / 6.1.176 / 6.6.143 or later
Fixed in 5.15.2106.1.1766.6.143
Vendor patch git.kernel.org →
Interim mitigation

Apply the kernel patch that implements skb_pull_data() validation in RFCOMM MCC handlers and update to a kernel version containing this fix.

Recommended fix High confidence

Linux Kernel 5.15.210, 6.1.176, 6.6.143, or 6.12.94 (depending on which version branch you are on)

  1. Identify the currently running Linux kernel version using `uname -r`
  2. Determine which version range your current kernel falls into from the affected ranges: < 5.15.210, < 6.1.176, < 6.6.143, or < 6.12.94
  3. For kernels in the < 5.15.210 range, upgrade to kernel version 5.15.210 or later
  4. For kernels in the >= 5.16, < 6.1.176 range, upgrade to kernel version 6.1.176 or later
  5. For kernels in the >= 6.2, < 6.6.143 range, upgrade to kernel version 6.6.143 or later
  6. For kernels in the >= 6.7, < 6.12.94 range, upgrade to kernel version 6.12.94 or later
  7. Apply the upgrade via your distribution's package manager (e.g., `apt-get dist-upgrade`, `yum update`, or `dnf upgrade`)
  8. Reboot the system to load the patched kernel
Caveat Kernel upgrades may require rebuilding third-party kernel modules; ensure compatibility with critical drivers before rebooting

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-53254 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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