MediumCVE-2025-21835

    Linux Kernel: Memory Leak (CVE-2025-21835)

    Published Last modified Sources: Siemens ProductCERT, BSI, SUSE, Debian LTS, CVE.org, EUVD

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_midi: fix MIDI Streaming descriptor lengths While the MIDI jacks are configured correctly, and the MIDIStreaming endpoint descriptors are filled with the correct information, bNumEmbMIDIJack and bLength are set incorrectly in these descriptors. This does not matter when the numbers of in and out ports are equal, but when they differ the host will receive broken descriptors with uninitialized stack memory leaking into the descriptor for whichever value is smaller.

    Update Linux Kernel to version 5.4.291, Linux Kernel to version 5.10.235, Linux Kernel to version 5.15.179.

    Affected
    • Linux Kernel lt 3.2..5.4.291
    • Linux Kernel lt 5.5..5.10.235
    • Linux Kernel lt 5.11..5.15.179
    • Linux Kernel lt 5.16..6.1.129
    • Linux Kernel lt 6.2..6.6.79
    • Linux Kernel lt 6.7..6.12.16
    • Linux Kernel lt 6.13..6.13.4
    Fixed in
    • Linux Kernel 5.4.291
    • Linux Kernel 5.10.235
    • Linux Kernel 5.15.179
    • Linux Kernel 6.1.129
    • Linux Kernel 6.6.79
    • Linux Kernel 6.12.16
    • Linux Kernel 6.13.4
    • Linux Kernel 6.14

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

    Metrics

    5.5

    Priority

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

    Source: NVD, CVSS v3

    5.5

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: Siemens ProductCERT, BSI, SUSE, Debian LTS, CVE.org, EUVD

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 13.9

    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
    37.13 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
    5.5 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
    5.5
    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
    0.2 %
    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
    13.9
    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: usb: gadget: f_midi: fix MIDI Streaming descriptor lengths While the MIDI jacks are configured correctly, and the MIDIStreaming endpoint descriptors are filled with the correct information, bNumEmbMIDIJack and bLength are set incorrectly in these descriptors. This does not matter when the numbers of in and out ports are equal, but when they differ the host will receive broken descriptors with uninitialized stack memory leaking into the descriptor for whichever value is smaller. The precise meaning of "in" and "out" in the port counts is not clearly defined and can be confusing. But elsewhere the driver consistently uses this to match the USB meaning of IN and OUT viewed from the host, so that "in" ports send data to the host and "out" ports receive data from it.

    Source: siemens_advisory, BSI CSAF, BSI WID Portal, suse_csaf, Debian LTS Advisories, cvelistv5, NVD (NIST), CVE.org (MITRE), ENISA EUVD

    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
    • 5.5 – < 5.10.235
    • —
    • 5.16 – < 6.1.129
    • 3.2 – < 5.4.291
    • 5.11 – < 5.15.179
    • 6.2 – < 6.6.79
    • 6.13 – < 6.13.4
    • 6.7 – < 6.12.16
    • 5.10.235
    • 6.14
    • 6.1.129
    • 5.4.291
    • 5.15.179
    • 6.6.79
    • 6.13.4
    • 6.12.16
    DellSecure Connect Gateway
    • < 5.30.0.14
    • 5.30.0.14
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbullseye
    Linuxdebianlinux-6.1bullseye
    Linuxlinuxlinux_kernel6.14
    Linuxlinuxlinux_kernel—

    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

      Show 24 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/3a983390d14e8498f303fc5cb23ab7d696b815db
      Referenceadded
      —
      https://git.kernel.org/stable/c/6ae6dee9f005a2f3b739b85abb6f14a0935699e0
      Referenceadded
      —
      https://git.kernel.org/stable/c/6b16761a928796e4b49e89a0b1ac284155172726
      Referenceadded
      —
      https://git.kernel.org/stable/c/9f36a89dcb78cb7e37f487b04a16396ac18c0636
      Referenceadded
      —
      https://git.kernel.org/stable/c/9f6860a9c11301b052225ca8825f8d2b1a5825bf
      Referenceadded
      —
      https://git.kernel.org/stable/c/a2d0694e1f111379c1efdf439dadd3cfd959fe9d
      Referenceadded
      —
      https://git.kernel.org/stable/c/d8e86700c8a8cf415e300a0921acd6a8f9b494f8
      Referenceadded
      —
      https://git.kernel.org/stable/c/da1668997052ed1cb00322e1f3b63702615c9429
      Referenceremoved
      https://git.kernel.org/stable/c/3a983390d14e8498f303fc5cb23ab7d696b815db
      —
      Referenceremoved
      https://git.kernel.org/stable/c/6ae6dee9f005a2f3b739b85abb6f14a0935699e0
      —
      Referenceremoved
      https://git.kernel.org/stable/c/6b16761a928796e4b49e89a0b1ac284155172726
      —
      Referenceremoved
      https://git.kernel.org/stable/c/9f36a89dcb78cb7e37f487b04a16396ac18c0636
      —
      Referenceremoved
      https://git.kernel.org/stable/c/9f6860a9c11301b052225ca8825f8d2b1a5825bf
      —
      Referenceremoved
      https://git.kernel.org/stable/c/a2d0694e1f111379c1efdf439dadd3cfd959fe9d
      —
      Referenceremoved
      https://git.kernel.org/stable/c/d8e86700c8a8cf415e300a0921acd6a8f9b494f8
      —
      Referenceremoved
      https://git.kernel.org/stable/c/da1668997052ed1cb00322e1f3b63702615c9429
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/3a983390d14e8498f303fc5cb23ab7d696b815db Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/6ae6dee9f005a2f3b739b85abb6f14a0935699e0 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/6b16761a928796e4b49e89a0b1ac284155172726 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/9f36a89dcb78cb7e37f487b04a16396ac18c0636 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/9f6860a9c11301b052225ca8825f8d2b1a5825bf Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/a2d0694e1f111379c1efdf439dadd3cfd959fe9d Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/d8e86700c8a8cf415e300a0921acd6a8f9b494f8 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/da1668997052ed1cb00322e1f3b63702615c9429 Types: Patch
      —

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

    2. Record modifiedCVE Program

      Show 4 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
      Referenceadded
      —
      https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
      Referenceremoved
      https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
      —
      Referenceremoved
      https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html
      —

      Source identifier: af854a3a-2127-422b-91ae-364da2661108

    3. Record modifiedSiemens ADP

      Show 4 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/2025/21xxx/CVE-2025-21835.json">CVE-2025-21835</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-265688.html
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html
      Referenceremoved
      https://cert-portal.siemens.com/productcert/html/ssa-265688.html
      —

      Source identifier: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

    Embed badge

    Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

    Badge preview for CVE-2025-21835
    <a href="https://intel.neosec.eu/en/cve/CVE-2025-21835"><img src="https://intel.neosec.eu/badge/cve/CVE-2025-21835.svg?lang=en" alt="CVE-2025-21835 – NEOSEC Intel" height="20"></a>