HighCVE-2025-59375

    libexpat Project libexpat: Allocation of Resources Without Limits or Throttling (CVE-2025-59375)

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

    What is affected, what to do

    A memory amplification vulnerability in libexpat allows attackers to trigger excessive dynamic memory allocations by submitting specially crafted XML input. A small input (~250 KiB) can cause the parser to allocate hundreds of megabytes, leading to denial-of-service (DoS) through memory exhaustion.

    An exploit is publicly available. Update libexpat Project libexpat to version 2.7.2.

    Affected
    • libexpat Project libexpat lt *..2.7.2
    Fixed in
    • libexpat Project libexpat 2.7.2

    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: NVD, CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

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

    1.4 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 72.0

    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
    89.87 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
    PoC (publicly reported)
    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
    1.4 %
    Moderate — model estimates 1-10% 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
    72.0
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    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
    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-770

    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 memory amplification vulnerability in libexpat allows attackers to trigger excessive dynamic memory allocations by submitting specially crafted XML input. A small input (~250 KiB) can cause the parser to allocate hundreds of megabytes, leading to denial-of-service (DoS) through memory exhaustion.

    Source: redhat_csaf, siemens_advisory, BSI WID Portal, BSI CSAF, suse_csaf, Debian LTS Advisories, NVD (NIST), cvelistv5, Debian Security Advisories, CVE.org (MITRE), Microsoft Security Update Guide, Ubuntu Security Notices, 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
    libexpat projectlibexpat
    • < 2.7.2
    • 2.7.2
    libexpat_projectlibexpat
    • < 2.7.2
    • 2.7.2
    ApplemacOS Sequoia
    • < 15.7.4
    • 15.7.4
    ApplemacOS Sonoma
    • < 14.8.4
    • 14.8.4
    ApplemacOS Tahoe
    • < 26.3
    • 26.3
    DellNetWorker vProxy
    • < 19.14
    • 19.14
    DellPowerScale OneFS Node Firmware Package
    • < 14.1
    • 14.1
    DellSecure Connect Gateway
    • < 5.34.00.16
    • 5.34.00.16
    F5BIG-IP
    • 21.0.0
    • 15.1.0-15.1.10
    • 16.1.0-16.1.6
    • 17.5.0-17.5.1
    • 17.1.0-17.1.3
    • —
    • —
    • —
    • —
    • —
    F5F5OS
    • A 1.8.0-1.8.3
    • C 1.6.0-1.6.4
    • C 1.8.0-1.8.2
    • A 1.5.1-1.5.4
    • —
    • —
    • —
    • —
    Hitachi EnergyRTU500
    • <CMU Firmware 12.7.8
    • <CMU Firmware 13.8.2
    • <CMU Firmware 13.7.8
    • —
    • —
    • —
    IBMHTTP Server
    • 8.5
    • 9
    • —
    • —
    IBMQRadar SIEM
    • <7.5.0 UP14 IF03
    • —
    IBMSecurity Verify Access
    • < 10.0.9.2
    • 10.0.9.2
    IBMSterling Connect:Direct
    • < 6.4.0.5
    • < 6.3.0.16
    • 6.4.0.5
    • 6.3.0.16
    MeinbergLANTIME
    • < 7.10.004
    • 7.10.004
    Open Sourceexpat
    • < 2.7.2
    • 2.7.2
    OracleFusion Middleware
    • 12.2.1.4.0
    • 14.1.1.0.0
    • 8.5.7
    • 14.1.2.1.0
    • 8.5.8
    • 15.1.1.0.0
    • 14.1.2.0.0
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    Red HatEnterprise Linux
    • Advanced Cluster Security
    • Update Infrastructure 5.1
    • —
    • —
    Tenable SecurityNessus
    • < 10.9.6
    • < 10.11.1
    • 10.9.6
    • 10.11.1
    Tenable SecurityNessus Network Monitor
    • < 6.5.3
    • 6.5.3
    XeroxFreeFlow Print Server
    • v7
    • v2
    • —
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Linuxdebianexpatbookworm
    Linuxdebianexpattrixie
    Linuxubuntuexpatbionic
    Linuxubuntuexpatfocal
    Linuxubuntuexpatjammy
    Linuxubuntuexpatnoble
    Linuxubuntuexpatresolute
    Linuxubuntuexpattrusty
    Linuxubuntuexpatxenial
    Linuxdebianfirefox-esrbookworm
    Linuxdebianfirefox-esrbullseye
    Linuxdebianfirefox-esrtrixie
    Linuxdebianthunderbirdbookworm
    Linuxdebianthunderbirdbullseye
    Linuxdebianthunderbirdtrixie

    Weakness classes (CWE)

    • CWE-770Allocation of Resources Without Limits or Throttling

      Base

      The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

      Entry at MITRE CWE-770

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    Reference tagged as exploitgithub.com (opens in a new tab)PoC (publicly reported)reported, not verified—

    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).

    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-2025-59375
    <a href="https://intel.neosec.eu/en/cve/CVE-2025-59375"><img src="https://intel.neosec.eu/badge/cve/CVE-2025-59375.svg?lang=en" alt="CVE-2025-59375 – NEOSEC Intel" height="20"></a>