MediumCVE-2026-104250

    unstructured: Stored XSS via unescaped HTML generation (CVE-2026-104250)

    Published Last modified Sources: CVE.org, OSV, Hersteller

    What is affected, what to do

    The unstructured library provides open-source components for ingesting and pre-processing images and text documents, such as PDFs, HTML, Word docs, and many more. Prior to 0.24.1, partition_html(html_parser_version="v2") and the VLM partitioner can preserve untrusted document tags, attributes, text, and link targets in metadata.text_as_html, while elements_to_html() emits the result as an HTML document.

    Update Unstructured to version 0.24.1.

    Affected
    • Unstructured lt *..0.24.1
    Fixed in
    • Unstructured 0.24.1

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

    Metrics

    6.1

    Priority

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

    Source: Vendor (CNA), CVSS v3

    6.1

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: CVE.org, OSV, Hersteller

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 8.5

    Show all metrics
    Severity
    Medium
    Priority score

    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
    61.07
    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
    6.1
    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
    6.1
    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
    8.5
    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
    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-79, CWE-116

    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

    The unstructured library provides open-source components for ingesting and pre-processing images and text documents, such as PDFs, HTML, Word docs, and many more. Prior to 0.24.1, partition_html(html_parser_version="v2") and the VLM partitioner can preserve untrusted document tags, attributes, text, and link targets in metadata.text_as_html, while elements_to_html() emits the result as an HTML document. The to_html() path in unstructured/documents/ontology.py does not escape output or reject unsafe URL schemes, allowing event-handler attributes, attribute breakout markup, and javascript: links to survive parsing. When the generated HTML or text_as_html is rendered in a browser, attacker-controlled script can execute in the viewer's origin, including in document-ingestion workflows where a privileged reviewer opens submitted content. This issue is fixed in version 0.24.1.

    Source: cvelistv5, NVD (NIST), OSV (Open Source Vulnerabilities), GitHub Security Advisories

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    VendorProductAffected versionsFixed in
    Unstructured-IOunstructured
    • < 0.24.1
    • 0.24.1
    pypiunstructured
    • 0.0.1.dev0
    • 0.10.0
    • 0.10.1
    • 0.10.10
    • 0.10.11
    • 0.10.12
    • 0.10.13
    • 0.10.14
    • 0.10.15
    • 0.10.16
    • 0.10.18
    • 0.10.19
    • 0.10.19.dev18
    • 0.10.2
    • 0.10.20
    • 0.10.21
    • 0.10.22
    • 0.10.23
    • 0.10.24
    • 0.10.25
    • 0.10.26
    • 0.10.27
    • 0.10.28
    • 0.10.29
    • 0.10.30
    • 0.10.4
    • 0.10.5
    • 0.10.6
    • 0.10.7
    • 0.10.8
    • 0.10.9
    • 0.11.0
    • 0.11.1
    • 0.11.2
    • 0.11.4
    • 0.11.5
    • 0.11.6
    • 0.11.7
    • 0.11.8
    • 0.12.0
    • 0.12.2
    • 0.12.3
    • 0.12.4
    • 0.12.5
    • 0.12.6
    • 0.13.0
    • 0.13.1
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    Weakness classes (CWE)

    • CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

      Base

      The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

      Entry at MITRE CWE-79

    • CWE-116Improper Encoding or Escaping of Output

      Class

      The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.

      Entry at MITRE CWE-116

    References & sources

    • github.comUnstructured-IO/unstructured/security/advisories/GHSA-v5mq-3xhg…x_refsource_CONFIRM
    • github.comUnstructured-IO/unstructured/pull/4394x_refsource_MISC
    • github.comUnstructured-IO/unstructured/commit/cda16b3f2170019be9c6ea56359…x_refsource_MISC
    • github.comUnstructured-IO/unstructured/releases/tag/0.24.1x_refsource_MISC
    • NVD (NIST)vuln/detail/CVE-2026-104250advisory
    • github.comUnstructured-IO/unstructuredpackage

    Reanalysis & status changes

    Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.

    1. CVE Modified134c704f-9b21-4f2e-91b3-4a467353bcc0

      • Reference: after https://github.com/Unstructured-IO/unstructured/security/advisories/GHSA-v5mq-3xhg-98m9
      • SSVC: after {"id":"CVE-2026-104250","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalI…

    2. New CVE Receivedsecurity-advisories@github.com

      • Description: after The unstructured library provides open-source components for ingesting and pre-processing images and text documents, such as PDFs, HTML, Word docs, and many more. Prior to 0.24.1, partition_html(html_parser_version="v2") and the VLM partitioner can preserve untrusted document tags, attributes, text, and link targets in metadata.text_as_html, while elements_to_html() emits the result as an HTML document. The to_html() path in unstructured/documents/ontology.py does not escape output or reject unsafe URL schemes, allowing event-handler attributes, attribute breakout markup, and javascript: links to survive parsing. When the generated HTML or text_as_html is rendered in a browser, attacker-controlled script can execute in the viewer's origin, including in document-ingestion workflows where a privileged reviewer opens submitted content. This issue is fixed in version 0.24.1.
      • CVSS V3.1: after AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
      • CWE: after CWE-79
      • CWE: after CWE-116