HighCVE-2025-21725

    Linux Kernel: security vulnerability (CVE-2025-21725)

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

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: smb: client: fix oops due to unset link speed It isn't guaranteed that NETWORK_INTERFACE_INFO::LinkSpeed will always be set by the server, so the client must handle any values and then prevent oopses like below from happening: Oops: divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 0 UID: 0 PID: 1323 Comm: cat Not tainted 6.13.0-rc7 #2 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-3.fc41 04/01/2014 RIP: 0010:cifs_debug_data_proc_show+0xa45/0x1460 [cifs] Code: 00 00 48 89 df e8 3b cd 1b c1 41 f6 44 24 2c 04 0f 84 50 01 00 00 48 89 ef e8 e7 d0 1b c1 49 8b 44 24 18 31 d2 49 8d 7c 24 28 <48> f7 74 24 18 48 89 c3 e8 6e cf 1b c1 41 8b 6c 24 28 49 8d 7c 24 RSP: 0018:ffffc90001817be0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88811230022c RCX: ffffffffc041bd99 RDX: 0000000000000000 RSI: 0000000000000567 RDI: ffff888112300228 RBP: ffff888112300218 R08: fffff52000302f5f R09: ffffed1022fa58ac R10: ffff888117d2c566 R11: 00000000fffffffe R12: ffff888112300200 R13: 000000012a15343f R14: 0000000000000001 R15: ffff888113f2db58 FS: 00007fe27119e740(0000) GS:ffff888148600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe2633c5000 CR3: 0000000124da0000 CR4: 0000000000750ef0 PKRU: 55555554 Call Trace: <TASK> ? __die_body.cold+0x19/0x27 ? die+0x2e/0x50 ? do_trap+0x159/0x1b0 ? cifs_debug_data_proc_show+0xa45/0x1460 [cifs] ? do_error_trap+0x90/0x130 ? cifs_debug_data_proc_show+0xa45/0x1460 [cifs] ? exc_divide_error+0x39/0x50 ? cifs_debug_data_proc_show+0xa45/0x1460 [cifs] ? asm_exc_divide_error+0x1a/0x20 ? cifs_debug_data_proc_show+0xa39/0x1460 [cifs] ? cifs_debug_data_proc_show+0xa45/0x1460 [cifs] ? seq_read_iter+0x42e/0x790 seq_read_iter+0x19a/0x790 proc_reg_read_iter+0xbe/0x110 ? __pfx_proc_reg_read_iter+0x10/0x10 vfs_read+0x469/0x570 ? do_user_addr_fault+0x398/0x760 ? __pfx_vfs_read+0x10/0x10 ? find_held_lock+0x8a/0xa0 ? __pfx_lock_release+0x10/0x10 ksys_read+0xd3/0x170 ? __pfx_ksys_read+0x10/0x10 ? __rcu_read_unlock+0x50/0x270 ? mark_held_locks+0x1a/0x90 do_syscall_64+0xbb/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe271288911 Code: 00 48 8b 15 01 25 10 00 f7 d8 64 89 02 b8 ff ff ff ff eb bd e8 20 ad 01 00 f3 0f 1e fa 80 3d b5 a7 10 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 4f c3 66 0f 1f 44 00 00 55 48 89 e5 48 83 ec RSP: 002b:00007ffe87c079d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000040000 RCX: 00007fe271288911 RDX: 0000000000040000 RSI: 00007fe2633c6000 RDI: 0000000000000003 RBP: 00007ffe87c07a00 R08: 0000000000000000 R09: 00007fe2713e6380 R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000040000 R13: 00007fe2633c6000 R14: 0000000000000003 R15: 0000000000000000 </TASK> Fix this by setting cifs_server_iface::speed to a sane value (1Gbps) by default when link speed is unset.

    Update Linux Kernel to version 6.1.129, Linux Kernel to version 6.6.76, Linux Kernel to version 6.12.13.

    Affected
    • Linux Kernel lt 6.1.65..6.1.129
    • Linux Kernel lt 6.6.4..6.6.76
    • Linux Kernel lt 6.7..6.12.13
    • Linux Kernel lt 6.13..6.13.2
    Fixed in
    • Linux Kernel 6.1.129
    • Linux Kernel 6.6.76
    • Linux Kernel 6.12.13
    • Linux Kernel 6.13.2
    • Linux Kernel 6.14

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

    Metrics

    7.5

    Priority

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

    Source: Vendor (CNA), CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

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

    0.4 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 33.6

    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
    54.55 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
    7.5 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
    7.5
    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
    0.4 %
    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
    33.6
    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
    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

    In the Linux kernel, the following vulnerability has been resolved: smb: client: fix oops due to unset link speed It isn't guaranteed that NETWORK_INTERFACE_INFO::LinkSpeed will always be set by the server, so the client must handle any values and then prevent oopses like below from happening: Oops: divide error: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 0 UID: 0 PID: 1323 Comm: cat Not tainted 6.13.0-rc7 #2 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-3.fc41 04/01/2014 RIP: 0010:cifs_debug_data_proc_show+0xa45/0x1460 [cifs] Code: 00 00 48 89 df e8 3b cd 1b c1 41 f6 44 24 2c 04 0f 84 50 01 00 00 48 89 ef e8 e7 d0 1b c1 49 8b 44 24 18 31 d2 49 8d 7c 24 28 <48> f7 74 24 18 48 89 c3 e8 6e cf 1b c1 41 8b 6c 24 28 49 8d 7c 24 RSP: 0018:ffffc90001817be0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88811230022c RCX: ffffffffc041bd99 RDX: 0000000000000000 RSI: 0000000000000567 RDI: ffff888112300228 RBP: ffff888112300218 R08: fffff52000302f5f R09: ffffed1022fa58ac R10: ffff888117d2c566 R11: 00000000fffffffe R12: ffff888112300200 R13: 000000012a15343f R14: 0000000000000001 R15: ffff888113f2db58 FS: 00007fe27119e740(0000) GS:ffff888148600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe2633c5000 CR3: 0000000124da0000 CR4: 0000000000750ef0 PKRU: 55555554 Call Trace: <TASK> ? __die_body.cold+0x19/0x27 ? die+0x2e/0x50 ? do_trap+0x159/0x1b0 ? cifs_debug_data_proc_show+0xa45/0x1460 [cifs] ? do_error_trap+0x90/0x130 ? cifs_debug_data_proc_show+0xa45/0x1460 [cifs] ? exc_divide_error+0x39/0x50 ? cifs_debug_data_proc_show+0xa45/0x1460 [cifs] ? asm_exc_divide_error+0x1a/0x20 ? cifs_debug_data_proc_show+0xa39/0x1460 [cifs] ? cifs_debug_data_proc_show+0xa45/0x1460 [cifs] ? seq_read_iter+0x42e/0x790 seq_read_iter+0x19a/0x790 proc_reg_read_iter+0xbe/0x110 ? __pfx_proc_reg_read_iter+0x10/0x10 vfs_read+0x469/0x570 ? do_user_addr_fault+0x398/0x760 ? __pfx_vfs_read+0x10/0x10 ? find_held_lock+0x8a/0xa0 ? __pfx_lock_release+0x10/0x10 ksys_read+0xd3/0x170 ? __pfx_ksys_read+0x10/0x10 ? __rcu_read_unlock+0x50/0x270 ? mark_held_locks+0x1a/0x90 do_syscall_64+0xbb/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe271288911 Code: 00 48 8b 15 01 25 10 00 f7 d8 64 89 02 b8 ff ff ff ff eb bd e8 20 ad 01 00 f3 0f 1e fa 80 3d b5 a7 10 00 00 74 13 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 4f c3 66 0f 1f 44 00 00 55 48 89 e5 48 83 ec RSP: 002b:00007ffe87c079d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000040000 RCX: 00007fe271288911 RDX: 0000000000040000 RSI: 00007fe2633c6000 RDI: 0000000000000003 RBP: 00007ffe87c07a00 R08: 0000000000000000 R09: 00007fe2713e6380 R10: 0000000000000022 R11: 0000000000000246 R12: 0000000000040000 R13: 00007fe2633c6000 R14: 0000000000000003 R15: 0000000000000000 </TASK> Fix this by setting cifs_server_iface::speed to a sane value (1Gbps) by default when link speed is unset.

    Source: BSI CSAF, BSI WID Portal, suse_csaf, Debian LTS Advisories, siemens_advisory, 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
    • 6.6.4 – < 6.6.76
    • 6.13 – < 6.13.2
    • —
    • 6.1.65 – < 6.1.129
    • 6.7 – < 6.12.13
    • 6.6.76
    • 6.13.2
    • 6.14
    • 6.1.129
    • 6.12.13
    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
    Linuxdebianlinux-6.1bullseye
    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 15 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/208e102a2fca44e40a6c3f7b9e2609cfd17a15aa
      Referenceadded
      —
      https://git.kernel.org/stable/c/3f901c35e1a1b3ed1b528a17ffdb941aa0294458
      Referenceadded
      —
      https://git.kernel.org/stable/c/699179dfc8d7da457b152ca5d18ae45f9ed9beaa
      Referenceadded
      —
      https://git.kernel.org/stable/c/ad3b49fbdb156aa8ee2026ba590642c9b5a410f2
      Referenceadded
      —
      https://git.kernel.org/stable/c/be7a6a77669588bfa5022a470989702bbbb11e7f
      Referenceremoved
      https://git.kernel.org/stable/c/208e102a2fca44e40a6c3f7b9e2609cfd17a15aa
      —
      Referenceremoved
      https://git.kernel.org/stable/c/3f901c35e1a1b3ed1b528a17ffdb941aa0294458
      —
      Referenceremoved
      https://git.kernel.org/stable/c/699179dfc8d7da457b152ca5d18ae45f9ed9beaa
      —
      Referenceremoved
      https://git.kernel.org/stable/c/ad3b49fbdb156aa8ee2026ba590642c9b5a410f2
      —
      Referenceremoved
      https://git.kernel.org/stable/c/be7a6a77669588bfa5022a470989702bbbb11e7f
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/208e102a2fca44e40a6c3f7b9e2609cfd17a15aa Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/3f901c35e1a1b3ed1b528a17ffdb941aa0294458 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/699179dfc8d7da457b152ca5d18ae45f9ed9beaa Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/ad3b49fbdb156aa8ee2026ba590642c9b5a410f2 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/be7a6a77669588bfa5022a470989702bbbb11e7f Types: Patch
      —

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

    2. Record modifiedCVE Program

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
      Referenceremoved
      https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
      —

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

    3. Record modifiedSiemens ADP

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2025/21xxx/CVE-2025-21725.json">CVE-2025-21725</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html

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

    4. Record modifiedLinux

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

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

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

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