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Linux KernelOperating system · Linux

CVE-2026-53364

MEDIUM · 5.5 CVSS v3.1 Published 2026-07-13
Fix available
A fix is available. Upgrade to 6.18.35 / 7.0.12 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click 5 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: hci_conn: Fix memory leak in hci_le_big_terminate() hci_le_big_terminate() allocates iso_list_data via kzalloc_obj but returns 0 without freeing it when neither pa_sync_term nor big_sync_term flags are set after evaluating the PA and BIG sync connection state. This early-return path was introduced when hci_le_big_terminate() was refactored to take struct hci_conn instead of raw u8 parameters, adding PA/BIG flag evaluation logic. The existing kfree() on hci_cmd_sync_queue failure does not cover this path.

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

In the Linux kernel Bluetooth subsystem, hci_le_big_terminate() allocates iso_list_data via kzalloc_obj but contains an early-return code path that fails to free this allocation when neither pa_sync_term nor big_sync_term flags are set after evaluating PA and BIG sync connection states. This creates a memory leak that occurs during ISO (Ischronous) connection handling in Bluetooth operations.

MitigationApply the upstream kernel patch which adds proper kfree() of iso_list_data in the early-return code path. Until the patch is available, monitor kernel memory usage for Bluetooth ISO operations.

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:>= 6.16.4, < 6.18.35>= 6.19, < 7.0.12= 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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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. Check kernel version
    Run 'uname -r' to get the running kernel version. Compare it against the affected ranges: >= 6.16.4 and < 6.18.35, or >= 6.19 and < 7.0.12, or exactly 7.1
    Affected if Kernel version falls within any of the affected version ranges
  2. Verify Bluetooth subsystem is active
    Run 'lsmod | grep bluetooth' or check 'rfkill list' to see if Bluetooth is enabled. Also check /sys/kernel/debug/bluetooth/ for active Bluetooth interfaces
    Affected if Bluetooth subsystem is loaded and active
  3. Confirm ISO (Ischronous) connection support
    Check if the kernel was built with CONFIG_BT_ISO=y by looking at /boot/config-$(uname -r) or running 'zcat /proc/config.gz | grep BT_ISO' if available
    Affected if CONFIG_BT_ISO is enabled in the kernel configuration
  4. Monitor for ISO-related memory allocation
    Use 'cat /proc/meminfo' and observe kernel memory usage patterns during active Bluetooth ISO operations. Check dmesg for any 'Bluetooth: ISO' or 'hci_le_big' related messages
    Affected if ISO connections are actively being created/terminated and memory is not being reclaimed
  5. Inspect the vulnerable function in kernel
    If kernel debug symbols are available, examine net/bluetooth/hci_event.c for the hci_le_big_terminate() function to verify if the kfree(iso_list_data) call exists after the early-return path for the flags check
    Affected if The patch adding kfree() in the early-return path is not applied (function still contains the memory leak)

A system is affected if it runs a vulnerable kernel version AND has Bluetooth ISO connections enabled and actively uses them, causing repeated unreleased memory allocations in hci_le_big_terminate().

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 6.18.35 / 7.0.12 or later
Fixed in 6.18.357.0.12
Interim mitigation

Apply the upstream kernel patch which adds proper kfree() of iso_list_data in the early-return code path. Until the patch is available, monitor kernel memory usage for Bluetooth ISO operations.

Recommended fix High confidence

Linux Kernel 6.18.35+ or 7.0.12+ or version beyond 7.1 (whichever corresponds to your current branch)

  1. Identify the current kernel version using `uname -r` or `cat /proc/version`
  2. Compare against the affected version ranges: >= 6.16.4 and < 6.18.35, >= 6.19 and < 7.0.12, or 7.1
  3. If affected, schedule a maintenance window for kernel upgrade
  4. Back up critical data before upgrading the kernel
  5. Upgrade to kernel version 6.18.35 or later (for 6.18.x branch), or 7.0.12 or later (for 7.0.x branch), or a version beyond 7.1 that includes the fix
  6. Reboot the system to load the new kernel
  7. Verify the fix is applied by checking the kernel version and confirming the memory leak is resolved
Caveat Kernel upgrades may require matching kernel modules or firmware; ensure compatibility with hardware drivers and deployed software before upgrading

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

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,920
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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-2026-53364 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
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