CriticalCVE-2026-119128

    ZITADEL 4.0.0 before 4.19.5 Login V2 Account Takeover via Forgeable verificationCheck Cookie (CVE-2026-119128)

    Published Last modified Sources: CVE.org, pwn.watch

    What is affected, what to do

    ZITADEL 4.0.0 before 4.19.5 contains an authentication bypass vulnerability in the Login V2 UI that allows unauthenticated attackers to set the first credential of users lacking any authentication method. Attackers can compute a valid verificationCheck cookie from the user ID and browser fingerprint to set a password, register a passkey, or link an identity provider, taking over the account.

    Update Zitadel to version 4.19.5.

    Affected
    • Zitadel lt 4.0.0..4.19.5
    Fixed in
    • Zitadel 4.19.5

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

    Metrics

    9.1

    Priority

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

    Source: Vendor (CNA), CVSS v4

    7.4

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org, pwn.watch

    —

    EPSS score

    No value is available for this vulnerability.

    Show all metrics
    Severity
    Critical
    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
    75.50 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
    9.1 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
    7.4
    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
    9.1
    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-565

    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

    ZITADEL 4.0.0 before 4.19.5 contains an authentication bypass vulnerability in the Login V2 UI that allows unauthenticated attackers to set the first credential of users lacking any authentication method. Attackers can compute a valid verificationCheck cookie from the user ID and browser fingerprint to set a password, register a passkey, or link an identity provider, taking over the account.

    Source: cvelistv5, NVD (NIST), pwn.watch

    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
    zitadelzitadel
    • 4.0.0 – < 4.19.5
    • 4.19.5

    Vendors and products

    Weakness classes (CWE)

    • CWE-565Reliance on Cookies without Validation and Integrity Checking

      Base

      The product relies on the existence or values of cookies when performing security-critical operations, but it does not properly ensure that the setting is valid for the associated user.

      Entry at MITRE CWE-565

    References & sources

    • github.comGitHub Security Advisory (GHSA-84fg-x5h4-w8xv)Vendor advisory, pwn-watch
    • vulncheck.comVulnCheck Advisory: ZITADEL 4.0.0 before 4.19.5 Login V2 Account Takeover via Forgeable verificationCheck CookieThird-party advisory
    • pwn.watchpwn.watch: ZITADEL: three Login V2 account takeover bugs (CVE-2026-119127, -119128, -119129), fixed in 4.19.5pwn-watch
    • github.comGHSA-mchc-246r-6m76: Login V2 host header injection (CVE-2026-119127)pwn-watch
    • github.comGHSA-qj3q-235g-qr6w: device authorization approval without consent (CVE-2026-119129)pwn-watch
    • CVE.org (MITRE)CVE-2026-119128: ZITADEL Login V2 account takeover via forgeable verificationCheck cookiepwn-watch
    • CVE.org (MITRE)CVE-2026-119127: ZITADEL Login V2 host header injectionpwn-watch
    • CVE.org (MITRE)CVE-2026-119129: ZITADEL device authorization approval account takeoverpwn-watch

    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. ReceivedVulnCheck

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

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

      Weakness type: CWE-565

      Description added or changed

      Show 7 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      ZITADEL 4.0.0 before 4.19.5 contains an authentication bypass vulnerability in the Login V2 UI that allows unauthenticated attackers to set the first credential of users lacking any authentication method. Attackers can compute a valid verificationCheck cookie from the user ID and browser fingerprint to set a password, register a passkey, or link an identity provider, taking over the account.
      CVSSadded
      —
      AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/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
      CVSSadded
      —
      AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
      Weakness type (CWE)added
      —
      CWE-565
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/119xxx/CVE-2026-119128.json">CVE-2026-119128</a>
      Referenceadded
      —
      https://github.com/zitadel/zitadel/security/advisories/GHSA-84fg-x5h4-w8xv
      Referenceadded
      —
      https://www.vulncheck.com/advisories/zitadel-4.0.0-before-4.19.5-login-v2-account-takeover-via-forgeable-verificationcheck-cookie

      Source identifier: disclosure@vulncheck.com

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