HighCVE-2026-19418

    TYPO3 CMS - Broken Access Control in Backend and Install Tool (CVE-2026-19418)

    Published Last modified Sources: TYPO3, Hersteller, BSI, CVE.org, OSV

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    What is affected, what to do

    The referrer enforcement introduced with TYPO3-CORE-SA-2020-006 (CVE-2020-11069) became ineffective in TYPO3 v13.0, where TYPO3 CMS started serving the backend and Install Tool applications from the site's main entry script instead of the dedicated typo3/ directory. Whether a request originated from the backend or Install Tool itself was determined by comparing the referrer against the directory of the entry script, which since then is the site root.

    Update TYPO3 CMS to version 13.4.34, TYPO3 CMS to version 14.3.6.

    Affected
    • TYPO3 CMS lt 13.0.0..13.4.34
    • TYPO3 CMS lt 14.0.0..14.3.6
    Fixed in
    • TYPO3 CMS 13.4.34
    • TYPO3 CMS 14.3.6

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

    Metrics

    7.3

    Priority

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

    Source: Vendor (CNA), CVSS v4

    7.3

    CVSS v4

    Severity High on the scale from 0 to 10.

    Source: TYPO3, Hersteller, BSI, CVE.org, OSV

    0.2 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 15.5

    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
    60.72 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
    7.3 Methodology
    CVSS v4

    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
    7.3
    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
    15.5
    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
    CISA assessment (SSVC)
    Exploitation: none known · not automatable · Technical impact: total
    Source: CISA Vulnrichment, as of 11 August 2026
    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-346, CWE-352

    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

    The referrer enforcement introduced with TYPO3-CORE-SA-2020-006 (CVE-2020-11069) became ineffective in TYPO3 v13.0, where TYPO3 CMS started serving the backend and Install Tool applications from the site's main entry script instead of the dedicated typo3/ directory. Whether a request originated from the backend or Install Tool itself was determined by comparing the referrer against the directory of the entry script, which since then is the site root. As a consequence, requests originating from any script running on one of the TYPO3 instance's own domains, such as a frontend page, were accepted by backend routes and Install Tool endpoints. Attackers able to execute JavaScript on one of those domains, for instance by exploiting a cross-site scripting vulnerability, could invoke these endpoints via Fetch/XHR with the privileges of an authenticated victim's user session. This issue affects TYPO3 CMS versions 13.0.0-13.4.33 and 14.0.0-14.3.5.

    Source: typo3_advisory, GitHub Security Advisories, BSI CSAF, BSI WID Portal, NVD (NIST), OSV (Open Source Vulnerabilities), cvelistv5

    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
    TYPO3TYPO3 CMS
    • 13.0.0 – < 13.4.34
    • 14.0.0 – < 14.3.6
    • 13.4.34
    • 14.3.6
    TYPO3Core
    • < 13.4.34
    • < 14.3.6
    • 13.4.34
    • 14.3.6
    packagisttypo3/cms-backend
    • v13.4.16
    • v13.0.1
    • v13.0.0
    • v13.4.27
    • v13.4.5
    • v13.1.0
    • v13.4.20
    • v13.4.3
    • 13.0.0
    • v13.4.13
    • v13.4.10
    • v13.4.23
    • v13.4.19
    • v13.4.15
    • v13.3.1
    • v13.4.24
    • v13.4.11
    • v13.4.14
    • v13.4.30
    • v13.4.12
    • v13.4.26
    • v13.2.1
    • v13.4.32
    • v13.4.8
    • v13.4.9
    • v13.4.0
    • v13.4.4
    • v13.4.25
    • v13.4.21
    • v13.4.29
    • v13.4.1
    • v13.4.33
    • v13.4.7
    • v13.1.1
    • v13.4.28
    • v13.4.2
    • v13.3.0
    • v13.4.17
    • v13.4.22
    • v13.4.18
    • v13.4.6
    • v13.4.31
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    packagisttypo3/cms-core
    • v14.1.0
    • v14.0.0
    • —
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    Vendors and products

    Weakness classes (CWE)

    • CWE-346Origin Validation Error

      Class

      The product does not properly verify that the source of data or communication is valid.

      Entry at MITRE CWE-346

    • CWE-352Cross-Site Request Forgery (CSRF)

      Compound

      The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.

      Entry at MITRE CWE-352

    References & sources

    • typo3.orgsecurity/advisory/typo3-core-sa-2026-021Vendor advisory
    • typo3.orgTYPO3-CORE-SA-2020-006 (previous fix of the same protection mechanism)related
    • github.comGit commit of main branchPatch
    • github.comGit commit of 14.3 branchPatch
    • github.comGit commit of 13.4 branchPatch
    • github.comTYPO3/typo3/security/advisories/GHSA-68jx-f42c-7599web
    • NVD (NIST)vuln/detail/CVE-2026-19418advisory
    • github.comFriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE…web
    • github.comTYPO3/typo3package
    • news.typo3.comsecurity/advisory/typo3-core-sa-2026-021web

    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 modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-19418","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-08-11T13:20:52.512047Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    2. Record modifiedTYPO3

      Description added or changed

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionchanged
      The referrer enforcement introduced with TYPO3-CORE-SA-2020-006 https://news.typo3.com/security/advisory/typo3-core-sa-2020-006 ( CVE-2020-11069 https://www.cve.org/CVERecord ) became ineffective in TYPO3 v13.0, where TYPO3 CMS started serving the backend and Install Tool applications from the site's main entry script instead of the dedicated typo3/ directory. Whether a request originated from the backend or Install Tool itself was determined by comparing the referrer against the directory of the entry script, which since then is the site root. As a consequence, requests originating from any script running on one of the TYPO3 instance's own domains, such as a frontend page, were accepted by backend routes and Install Tool endpoints. Attackers able to execute JavaScript on one of those domains, for instance by exploiting a cross-site scripting vulnerability, could invoke these endpoints via Fetch/XHR with the privileges of an authenticated victim's user session. This issue affects TYPO3 CMS versions 13.0.0-13.4.33 and 14.0.0-14.3.5.
      The referrer enforcement introduced with TYPO3-CORE-SA-2020-006 (CVE-2020-11069) became ineffective in TYPO3 v13.0, where TYPO3 CMS started serving the backend and Install Tool applications from the site's main entry script instead of the dedicated typo3/ directory. Whether a request originated from the backend or Install Tool itself was determined by comparing the referrer against the directory of the entry script, which since then is the site root. As a consequence, requests originating from any script running on one of the TYPO3 instance's own domains, such as a frontend page, were accepted by backend routes and Install Tool endpoints. Attackers able to execute JavaScript on one of those domains, for instance by exploiting a cross-site scripting vulnerability, could invoke these endpoints via Fetch/XHR with the privileges of an authenticated victim's user session. This issue affects TYPO3 CMS versions 13.0.0-13.4.33 and 14.0.0-14.3.5.

      Source identifier: f4fb688c-4412-4426-b4b8-421ecf27b14a

    3. ReceivedTYPO3

      CVSS V4.0: AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

      Weakness type: CWE-352, CWE-346

      Description added or changed

      Show 10 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      TYPO3 CMS, TYPO3 CMS, TYPO3 CMS
      Descriptionadded
      —
      The referrer enforcement introduced with TYPO3-CORE-SA-2020-006 https://news.typo3.com/security/advisory/typo3-core-sa-2020-006 ( CVE-2020-11069 https://www.cve.org/CVERecord ) became ineffective in TYPO3 v13.0, where TYPO3 CMS started serving the backend and Install Tool applications from the site's main entry script instead of the dedicated typo3/ directory. Whether a request originated from the backend or Install Tool itself was determined by comparing the referrer against the directory of the entry script, which since then is the site root. As a consequence, requests originating from any script running on one of the TYPO3 instance's own domains, such as a frontend page, were accepted by backend routes and Install Tool endpoints. Attackers able to execute JavaScript on one of those domains, for instance by exploiting a cross-site scripting vulnerability, could invoke these endpoints via Fetch/XHR with the privileges of an authenticated victim's user session. This issue affects TYPO3 CMS versions 13.0.0-13.4.33 and 14.0.0-14.3.5.
      CVSSadded
      —
      AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
      Weakness type (CWE)added
      —
      CWE-352
      Weakness type (CWE)added
      —
      CWE-346
      Referenceadded
      —
      https://github.com/TYPO3/typo3/commit/4a75e862c589c85d795d7c65dcdc835f8f413efc
      Referenceadded
      —
      https://github.com/TYPO3/typo3/commit/a0e8ee06a40e959b9e7b06a4b1cb19d3a0d3dcf7
      Referenceadded
      —
      https://github.com/TYPO3/typo3/commit/ae0abd329d52285fe6e92804c3608820ad45e872
      Referenceadded
      —
      https://typo3.org/security/advisory/typo3-core-sa-2020-006
      Referenceadded
      —
      https://typo3.org/security/advisory/typo3-core-sa-2026-021

      Source identifier: f4fb688c-4412-4426-b4b8-421ecf27b14a

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