MediumCVE-2026-80914

    Linux Kernel: Use-After-Free (CVE-2026-80914)

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

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    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: fix use-after-free of listener socket in iso_conn_ready iso_conn_ready() looks up the BIS listener socket with iso_get_sock(), which takes a reference, and then, without re-checking its state, creates a child socket from it: parent = iso_get_sock(hdev, ...); if (!parent) return; lock_sock(parent); sk = iso_sock_alloc(sock_net(parent), NULL, BTPROTO_ISO, ...); ... iso_chan_add(conn, sk, parent); ... release_sock(parent); sock_put(parent); If the listener socket is closed concurrently, between iso_get_sock() and lock_sock(), the reference taken by iso_get_sock() may be the last one: the close path drops the link-list reference, and once iso_conn_ready() drops its own reference at the end of the function the socket is freed. The child socket, however, is already linked to the freed parent, and a later disconnect of the child runs iso_chan_del() -> bt_accept_unlink(), which dereferences the dangling parent pointer into the freed accept queue (a use-after-free).

    Update Linux Kernel to version 6.1.188, Linux Kernel to version 6.6.157, Linux Kernel to version 6.12.109.

    Affected
    • Linux Kernel lt 6.0..6.1.188
    • Linux Kernel lt 6.2..6.6.157
    • Linux Kernel lt 6.7..6.12.109
    • Linux Kernel lt 6.13..6.18.50
    • Linux Kernel lt 6.19..7.2.4
    Fixed in
    • Linux Kernel 6.1.188
    • Linux Kernel 6.6.157
    • Linux Kernel 6.12.109
    • Linux Kernel 6.18.50
    • Linux Kernel 7.2.4
    • Linux Kernel 7.3

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

    Metrics

    4.2

    XIEM Effective CVSS

    Highest available CVSS rating from NVD and vendor data.

    Source: Vendor (CNA), CVSS v3

    4.2

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: HKCERT, Debian LTS, Ubuntu, Debian, SUSE, Msrc Update Guide, EUVD, CVE.org, BSI

    0.4 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 31.0

    Show all metrics
    Severity
    Medium
    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
    53.08 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
    4.2 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
    4.2
    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
    0.4 %
    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
    31.0
    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

    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
    Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
    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

    In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: fix use-after-free of listener socket in iso_conn_ready iso_conn_ready() looks up the BIS listener socket with iso_get_sock(), which takes a reference, and then, without re-checking its state, creates a child socket from it: parent = iso_get_sock(hdev, ...); if (!parent) return; lock_sock(parent); sk = iso_sock_alloc(sock_net(parent), NULL, BTPROTO_ISO, ...); ... iso_chan_add(conn, sk, parent); ... release_sock(parent); sock_put(parent); If the listener socket is closed concurrently, between iso_get_sock() and lock_sock(), the reference taken by iso_get_sock() may be the last one: the close path drops the link-list reference, and once iso_conn_ready() drops its own reference at the end of the function the socket is freed. The child socket, however, is already linked to the freed parent, and a later disconnect of the child runs iso_chan_del() -> bt_accept_unlink(), which dereferences the dangling parent pointer into the freed accept queue (a use-after-free). The same dangling pointer is also dereferenced through parent->***() in iso_chan_del(). Fix it the same way the connected (non-BIS) path was fixed in commit 0d255e63fcf3 ("Bluetooth: ISO: hold sk properly in iso_conn_ready"): after taking the socket lock, re-check that the parent is still a listening, alive socket, and bail out otherwise.

    Source: HKCERT (CC BY 3.0 HK) · HKCERT rating: medium, Debian LTS Advisories, Ubuntu Security Notices, Debian Security Advisories, suse_csaf, Microsoft Security Update Guide, ENISA EUVD, cvelistv5, NVD (NIST), BSI WID Portal, BSI CSAF

    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
    • —
    • 6.2 – < 6.6.157
    • 6.13 – < 6.18.50
    • 6.19 – < 7.2.4
    • 6.7 – < 6.12.109
    • 6.0 – < 6.1.188
    • 7.3
    • 6.6.157
    • 6.18.50
    • 7.2.4
    • 6.12.109
    • 6.1.188

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxtrixie
    Linuxubuntulinuxnoble
    Linuxubuntulinuxresolute
    Linuxdebianlinux-6.12bookworm
    Linuxubuntulinux-awsnoble
    Linuxubuntulinux-awsresolute
    Linuxubuntulinux-aws-6.8jammy
    Linuxubuntulinux-aws-7.0noble
    Linuxubuntulinux-aws-fipsnoble
    Linuxubuntulinux-azurenoble
    Linuxubuntulinux-azureresolute
    Linuxubuntulinux-azure-6.8jammy
    Linuxubuntulinux-azure-fdenoble
    Linuxubuntulinux-azure-fderesolute
    Linuxubuntulinux-azure-fde-6.8jammy
    Linuxubuntulinux-azure-fde-7.0noble
    Linuxubuntulinux-azure-fipsnoble
    Linuxubuntulinux-gcpnoble
    Linuxubuntulinux-gcpresolute
    Linuxubuntulinux-gcp-6.8jammy
    Linuxubuntulinux-gcp-7.0noble
    Linuxubuntulinux-gcp-fipsnoble
    Linuxubuntulinux-gkenoble

    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 modifiedLinux

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/80xxx/CVE-2026-80914.json">CVE-2026-80914</a>

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

    2. Record modifiedLinux

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/80xxx/CVE-2026-80914.json">CVE-2026-80914</a>
      Referenceadded
      —
      https://git.kernel.org/stable/c/1702f12cf59a1c3b670eb6bb4a4d6fcccf07e3b8
      Referenceadded
      —
      https://git.kernel.org/stable/c/d47b8f8c02a3d3f282693e5a4ff1f6b4b00518de

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

    3. Record modifiedLinux

      CVSS V3.1: AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      CVSSadded
      —
      AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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

    4. ReceivedLinux

      Description added or changed

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      In the Linux kernel, the following vulnerability has been resolved: Bluetooth: ISO: fix use-after-free of listener socket in iso_conn_ready iso_conn_ready() looks up the BIS listener socket with iso_get_sock(), which takes a reference, and then, without re-checking its state, creates a child socket from it: parent = iso_get_sock(hdev, ...); if (!parent) return; lock_sock(parent); sk = iso_sock_alloc(sock_net(parent), NULL, BTPROTO_ISO, ...); ... iso_chan_add(conn, sk, parent); ... release_sock(parent); sock_put(parent); If the listener socket is closed concurrently, between iso_get_sock() and lock_sock(), the reference taken by iso_get_sock() may be the last one: the close path drops the link-list reference, and once iso_conn_ready() drops its own reference at the end of the function the socket is freed. The child socket, however, is already linked to the freed parent, and a later disconnect of the child runs iso_chan_del() -> bt_accept_unlink(), which dereferences the dangling parent pointer into the freed accept queue (a use-after-free). The same dangling pointer is also dereferenced through parent->***() in iso_chan_del(). Fix it the same way the connected (non-BIS) path was fixed in commit 0d255e63fcf3 ("Bluetooth: ISO: hold sk properly in iso_conn_ready"): after taking the socket lock, re-check that the parent is still a listening, alive socket, and bail out otherwise.
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/80xxx/CVE-2026-80914.json">CVE-2026-80914</a>
      Referenceadded
      —
      https://git.kernel.org/stable/c/03288b7447c9e572f8ab82fc29cfb4ca719ab210
      Referenceadded
      —
      https://git.kernel.org/stable/c/2387cd06a2c0b416f05028b02bba1089f54c28d9
      Referenceadded
      —
      https://git.kernel.org/stable/c/49fd7116f76b860b230843700fb7423ab5331e1f
      Referenceadded
      —
      https://git.kernel.org/stable/c/560bef609fa5992745929e8d7d458b9d88dd2830

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

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