MediumCVE-2025-39748

    Linux Kernel: security vulnerability (CVE-2025-39748)

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

    What is affected, what to do

    In the Linux kernel, the following vulnerability has been resolved: bpf: Forget ranges when refining tnum after JSET Syzbot reported a kernel warning due to a range invariant violation on the following BPF program. 0: call bpf_get_netns_cookie 1: if r0 == 0 goto <exit> 2: if r0 & Oxffffffff goto <exit> The issue is on the path where we fall through both jumps. That path is unreachable at runtime: after insn 1, we know r0 != 0, but with the sign extension on the jset, we would only fallthrough insn 2 if r0 == 0. Unfortunately, is_branch_taken() isn't currently able to figure this out, so the verifier walks all branches.

    Update Linux Kernel to version 5.10.253, Linux Kernel to version 5.15.203, Linux Kernel to version 6.1.167.

    Affected
    • Linux Kernel lt 5.0..5.10.253
    • Linux Kernel lt 5.11..5.15.203
    • Linux Kernel lt 5.16..6.1.167
    • Linux Kernel lt 6.2..6.6.130
    • Linux Kernel lt 6.7..6.12.43
    • Linux Kernel lt 6.13..6.15.11
    • Linux Kernel lt 6.16..6.16.2
    Fixed in
    • Linux Kernel 5.10.253
    • Linux Kernel 5.15.203
    • Linux Kernel 6.1.167
    • Linux Kernel 6.6.130
    • Linux Kernel 6.12.43
    • Linux Kernel 6.15.11
    • Linux Kernel 6.16.2
    • Linux Kernel 6.17

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

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 6.8

    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
    38.72 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
    6.8
    Low — this CVE sits in the lower 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: bpf: Forget ranges when refining tnum after JSET Syzbot reported a kernel warning due to a range invariant violation on the following BPF program. 0: call bpf_get_netns_cookie 1: if r0 == 0 goto <exit> 2: if r0 & Oxffffffff goto <exit> The issue is on the path where we fall through both jumps. That path is unreachable at runtime: after insn 1, we know r0 != 0, but with the sign extension on the jset, we would only fallthrough insn 2 if r0 == 0. Unfortunately, is_branch_taken() isn't currently able to figure this out, so the verifier walks all branches. The verifier then refines the register bounds using the second condition and we end up with inconsistent bounds on this unreachable path: 1: if r0 == 0 goto <exit> r0: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0xffffffffffffffff) 2: if r0 & 0xffffffff goto <exit> r0 before reg_bounds_sync: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0) r0 after reg_bounds_sync: u64=[0x1, 0] var_off=(0, 0) Improving the range refinement for JSET to cover all cases is tricky. We also don't expect many users to rely on JSET given LLVM doesn't generate those instructions. So instead of improving the range refinement for JSETs, Eduard suggested we forget the ranges whenever we're narrowing tnums after a JSET. This patch implements that approach.

    Source: siemens_advisory, Debian LTS Advisories, Debian Security Advisories, suse_csaf, Ubuntu Security Notices, BSI WID Portal, BSI CSAF, NVD (NIST), cvelistv5, Microsoft Security Update Guide, 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
    • 6.2 – < 6.6.130
    • 6.16 – < 6.16.2
    • 5.11 – < 5.15.203
    • 6.13 – < 6.15.11
    • 6.7 – < 6.12.43
    • —
    • 5.16 – < 6.1.167
    • 5.0 – < 5.10.253
    • 6.6.130
    • 6.16.2
    • 5.15.203
    • 6.15.11
    • 6.12.43
    • 6.17
    • 6.1.167
    • 5.10.253
    SiemensSIMATIC S7
    • 1500 TM MFP V1.1.1 GNU/Linux subsystem
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianlinuxbookworm
    Linuxdebianlinuxbullseye
    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 20 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://git.kernel.org/stable/c/0643aa2468192a4d81326e8e76543854870b1ee2
      Referenceadded
      —
      https://git.kernel.org/stable/c/22191359f8454b0be082c3b126f86bcbea0f1318
      Referenceadded
      —
      https://git.kernel.org/stable/c/2fd0c26bacd90ef26522bd3169000a4715bf151f
      Referenceadded
      —
      https://git.kernel.org/stable/c/591c788d16046edb0220800bf1819554af5853ce
      Referenceadded
      —
      https://git.kernel.org/stable/c/6279846b9b2532e1b04559ef8bd0dec049f29383
      Referenceadded
      —
      https://git.kernel.org/stable/c/80a6b11862a7cfdf691e8f9faee89cfea219f098
      Referenceadded
      —
      https://git.kernel.org/stable/c/c29dd8336236a4deb75596b52d2dd16ccc4a380d
      Referenceadded
      —
      https://git.kernel.org/stable/c/f01e06930444cab289a8783017af9b64255bd103
      Referenceremoved
      https://git.kernel.org/stable/c/0643aa2468192a4d81326e8e76543854870b1ee2
      —
      Referenceremoved
      https://git.kernel.org/stable/c/22191359f8454b0be082c3b126f86bcbea0f1318
      —
      Referenceremoved
      https://git.kernel.org/stable/c/2fd0c26bacd90ef26522bd3169000a4715bf151f
      —
      Referenceremoved
      https://git.kernel.org/stable/c/591c788d16046edb0220800bf1819554af5853ce
      —
      Referenceremoved
      https://git.kernel.org/stable/c/6279846b9b2532e1b04559ef8bd0dec049f29383
      —
      Referenceremoved
      https://git.kernel.org/stable/c/80a6b11862a7cfdf691e8f9faee89cfea219f098
      —
      Referenceremoved
      https://git.kernel.org/stable/c/c29dd8336236a4deb75596b52d2dd16ccc4a380d
      —
      Referenceremoved
      https://git.kernel.org/stable/c/f01e06930444cab289a8783017af9b64255bd103
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/2fd0c26bacd90ef26522bd3169000a4715bf151f Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/6279846b9b2532e1b04559ef8bd0dec049f29383 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/80a6b11862a7cfdf691e8f9faee89cfea219f098 Types: Patch
      —
      Reference typeremoved
      https://git.kernel.org/stable/c/f01e06930444cab289a8783017af9b64255bd103 Types: Patch
      —

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

    2. Record modifiedSiemens ADP

      Show 7 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/2025/39xxx/CVE-2025-39748.json">CVE-2025-39748</a>
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-019113.html
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-082556.html
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-457936.html
      Referenceadded
      —
      https://cert-portal.siemens.com/productcert/html/ssa-784472.html
      Referenceremoved
      https://cert-portal.siemens.com/productcert/html/ssa-019113.html
      —
      Referenceremoved
      https://cert-portal.siemens.com/productcert/html/ssa-082556.html
      —

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

    One NVD translation into another language is hidden.

    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-2025-39748
    <a href="https://intel.neosec.eu/en/cve/CVE-2025-39748"><img src="https://intel.neosec.eu/badge/cve/CVE-2025-39748.svg?lang=en" alt="CVE-2025-39748 – NEOSEC Intel" height="20"></a>