HighCVE-2026-53357

    Linux Kernel: Use After Free (CVE-2026-53357)

    Published Last modified Sources: SUSE, Debian LTS, Ubuntu, Red Hat, BSI, CVE.org, Msrc Update Guide

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    What is affected, what to do

    A flaw was found in the Linux kernel's Bluetooth component. A Use-After-Free (UAF) vulnerability exists in the `l2cap_sock_cleanup_listen()` and `l2cap_conn_del()` functions.

    Update Linux Kernel to version 5.10.259, Linux Kernel to version 5.15.210, Linux Kernel to version 6.1.175.

    Affected
    • Linux Kernel lt 5.7..5.10.259
    • Linux Kernel lt 5.11..5.15.210
    • Linux Kernel lt 5.16..6.1.175
    • Linux Kernel lt 6.2..6.6.142
    • Linux Kernel lt 6.7..6.12.92
    • Linux Kernel lt 6.13..6.18.34
    • Linux Kernel lt 6.19..7.0.11
    Fixed in
    • Linux Kernel 5.10.259
    • Linux Kernel 5.15.210
    • Linux Kernel 6.1.175
    • Linux Kernel 6.6.142
    • Linux Kernel 6.12.92
    • Linux Kernel 6.18.34
    • Linux Kernel 7.0.11
    • Linux Kernel 7.1

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    8.0

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v3

    8.0

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: SUSE, Debian LTS, Ubuntu, Red Hat, BSI, CVE.org, Msrc Update Guide

    0.3 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 26.5

    Show all metrics
    Severity
    High
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    65.20 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    no public PoC known
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    8.0 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    8.0
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.3 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    26.5
    Elevated — this CVE ranks above at least 10% of all CVEs scored today.
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    —
    Published
    CISA assessment (SSVC)
    Exploitation: none known · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 16 October 2026
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-416

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    A flaw was found in the Linux kernel's Bluetooth component. A Use-After-Free (UAF) vulnerability exists in the `l2cap_sock_cleanup_listen()` and `l2cap_conn_del()` functions. This flaw occurs due to a race condition during the cleanup of a listening socket and a concurrent Bluetooth (HCI) disconnect. An unprivileged local attacker could potentially exploit this to cause a system crash, leading to a Denial of Service (DoS).

    Source: suse_csaf, Debian LTS Advisories, Ubuntu Security Notices, redhat_csaf, BSI WID Portal, BSI CSAF, NVD (NIST), cvelistv5, Microsoft Security Update Guide

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    LinuxLinux
    • 5.16 – < 6.1.175
    • 6.19 – < 7.0.11
    • 5.11 – < 5.15.210
    • 5.7 – < 5.10.259
    • 6.13 – < 6.18.34
    • —
    • 6.7 – < 6.12.92
    • 6.2 – < 6.6.142
    • 6.1.175
    • 7.0.11
    • 5.15.210
    • 5.10.259
    • 6.18.34
    • 7.1
    • 6.12.92
    • 6.6.142
    Open SourceLinux Kernel
    • < 6.18.35
    • < 5.15.210
    • < 7.0.12
    • < 6.1.176
    • < 6.6.143
    • < 6.12.93
    • < 7.1
    • < 5.10.259
    • 6.18.35
    • 5.15.210
    • 7.0.12
    • 6.1.176
    • 6.6.143
    • 6.12.93
    • 7.1
    • 5.10.259

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    Linuxdebianlinux-6.1bullseye
    Linuxubuntulinux-aws-fipsnoble
    Linuxubuntulinux-ibm-6.8jammy
    Linuxubuntulinux-nvidiajammy
    Linuxubuntulinux-nvidia-tegrajammy
    Linuxubuntulinux-nvidia-tegra-5.15focal
    Linuxubuntulinux-nvidia-tegra-igxjammy
    Linuxlinuxlinux_kernel7.1
    Linuxlinuxlinux_kernel—

    Weakness classes (CWE)

    • CWE-416Use After Free

      Variant

      The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

      Entry at MITRE CWE-416

    References & sources

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedCISA ADP

      Weakness type: CWE-416

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-416

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. Record modifiedLinux

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/407217734835d21d4e0105ebf347860dc1806f88
      Referenceadded
      —
      https://git.kernel.org/stable/c/5d86d2f1b4d9a508c441d3e45277ae1a73cfed57
      Referenceadded
      —
      https://git.kernel.org/stable/c/751de6ec671fe75ad9cf65a0638d2a06b6a5984d
      Referenceadded
      —
      https://git.kernel.org/stable/c/7eebd4c2c86f573af87ff165d08a83432eb0b919
      Referenceadded
      —
      https://git.kernel.org/stable/c/87c543e2f78d0871f271df92dab98901bbd5b6f5
      Referenceadded
      —
      https://git.kernel.org/stable/c/a5ca86a6097a8b030ca3226cd300b17ed330f966
      Referenceadded
      —
      https://git.kernel.org/stable/c/ab1513597c6cf17cd1ad2a21e3b045421b48e022
      Referenceadded
      —
      https://git.kernel.org/stable/c/added1213395071470a900cc845a042fb51882a6
      Referenceremoved
      https://git.kernel.org/stable/c/407217734835d21d4e0105ebf347860dc1806f88
      —
      Referenceremoved
      https://git.kernel.org/stable/c/5d86d2f1b4d9a508c441d3e45277ae1a73cfed57
      —
      Referenceremoved
      https://git.kernel.org/stable/c/751de6ec671fe75ad9cf65a0638d2a06b6a5984d
      —
      Referenceremoved
      https://git.kernel.org/stable/c/7eebd4c2c86f573af87ff165d08a83432eb0b919
      —
      Referenceremoved
      https://git.kernel.org/stable/c/87c543e2f78d0871f271df92dab98901bbd5b6f5
      —
      Referenceremoved
      https://git.kernel.org/stable/c/a5ca86a6097a8b030ca3226cd300b17ed330f966
      —
      Referenceremoved
      https://git.kernel.org/stable/c/ab1513597c6cf17cd1ad2a21e3b045421b48e022
      —
      Referenceremoved
      https://git.kernel.org/stable/c/added1213395071470a900cc845a042fb51882a6
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/407217734835d21d4e0105ebf347860dc1806f88 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/5d86d2f1b4d9a508c441d3e45277ae1a73cfed57 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/751de6ec671fe75ad9cf65a0638d2a06b6a5984d Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/7eebd4c2c86f573af87ff165d08a83432eb0b919 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/87c543e2f78d0871f271df92dab98901bbd5b6f5 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/a5ca86a6097a8b030ca3226cd300b17ed330f966 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/ab1513597c6cf17cd1ad2a21e3b045421b48e022 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/added1213395071470a900cc845a042fb51882a6 Types: Patch
      —

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

    3. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-53357","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:28:47.902686Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    4. Initial analysis by NVDNVD

      Newly listed as affected:
      • Linux Kernel (5.16 – before 6.1.175; 6.7 – before 6.12.92; 6.13 – before 6.18.34; 6.19 – before 7.0.11; 6.2 – before 6.6.142; 5.11 – before 5.15.210; 5.7 – before 5.10.259; 4 individual versions)

      Weakness type: CWE-416

      Show 10 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Weakness type (CWE)added
      —
      CWE-416
      Product configurationadded
      —
      OR *cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.175 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.92 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.34 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.0.11 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.142 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.210 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.7 up to (excluding) 5.10.259
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/407217734835d21d4e0105ebf347860dc1806f88 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/5d86d2f1b4d9a508c441d3e45277ae1a73cfed57 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/751de6ec671fe75ad9cf65a0638d2a06b6a5984d Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/7eebd4c2c86f573af87ff165d08a83432eb0b919 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/87c543e2f78d0871f271df92dab98901bbd5b6f5 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/a5ca86a6097a8b030ca3226cd300b17ed330f966 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/ab1513597c6cf17cd1ad2a21e3b045421b48e022 Types: Patch
      Reference typeadded
      —
      kernel.org: https://git.kernel.org/stable/c/added1213395071470a900cc845a042fb51882a6 Types: Patch

      Source identifier: nvd@nist.gov

    5. ReceivedLinux

      Description added or changed

      Show 10 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Linux, Linux
      Descriptionadded
      —
      In the Linux kernel, the following vulnerability has been resolved: Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del() bt_accept_dequeue() unlinks a not-yet-accepted child from the parent accept queue and release_sock()s it before returning, so the returned sk has no caller reference and is unlocked. l2cap_sock_cleanup_listen() walks these children on listening-socket close. A concurrent HCI disconnect drives hci_rx_work -> l2cap_conn_del() which runs l2cap_chan_del() + l2cap_sock_kill() and frees the child sk and its l2cap_chan; cleanup_listen() then uses both: BUG: KASAN: slab-use-after-free in l2cap_sock_kill l2cap_sock_kill / l2cap_sock_cleanup_listen / __x64_sys_close Freed by: l2cap_conn_del -> l2cap_sock_close_cb -> l2cap_sock_kill This is distinct from the two fixes already in this area: commit e83f5e24da741 ("Bluetooth: serialize accept_q access") serialises the accept_q list/poll and takes temporary refs inside bt_accept_dequeue(), and CVE-2025-39860 serialises the userspace close()/accept() race by calling cleanup_listen() under lock_sock() in l2cap_sock_release(). Neither covers l2cap_conn_del() running from hci_rx_work, so this UAF still reproduces on current bluetooth/master. Take the reference at the source: bt_accept_dequeue() does sock_hold() while sk is still locked, before release_sock(); callers sock_put(). cleanup_listen() pins the chan with l2cap_chan_hold_unless_zero() under a brief child sk lock (serialising vs l2cap_sock_teardown_cb()), drops it before l2cap_chan_lock(), and skips a duplicate l2cap_sock_kill() on SOCK_DEAD. conn->lock is not taken here: cleanup_listen() runs under the parent sk lock and that would invert conn->lock -> chan->lock -> sk_lock (lockdep). KASAN/SMP: an unprivileged listen/close vs HCI-disconnect race produced 12 use-after-free reports per run before this change; 0, and no lockdep report, over 1600+ raced iterations after it on bluetooth/master.
      Referenceadded
      —
      https://git.kernel.org/stable/c/407217734835d21d4e0105ebf347860dc1806f88
      Referenceadded
      —
      https://git.kernel.org/stable/c/5d86d2f1b4d9a508c441d3e45277ae1a73cfed57
      Referenceadded
      —
      https://git.kernel.org/stable/c/751de6ec671fe75ad9cf65a0638d2a06b6a5984d
      Referenceadded
      —
      https://git.kernel.org/stable/c/7eebd4c2c86f573af87ff165d08a83432eb0b919
      Referenceadded
      —
      https://git.kernel.org/stable/c/87c543e2f78d0871f271df92dab98901bbd5b6f5
      Referenceadded
      —
      https://git.kernel.org/stable/c/a5ca86a6097a8b030ca3226cd300b17ed330f966
      Referenceadded
      —
      https://git.kernel.org/stable/c/ab1513597c6cf17cd1ad2a21e3b045421b48e022
      Referenceadded
      —
      https://git.kernel.org/stable/c/added1213395071470a900cc845a042fb51882a6

      Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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