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    CVE-2023-39953

    user_oidc provides the OIDC connect user backend for Nextcloud, an open-source cloud platform. Starting in version 1.0.0 and prior to version 1.3.3, missing verification of the issuer would have allowed an attacker to perform a man-in-the-middle attack returning corrupted or known token they also have access to. user_oidc 1.3.3 contains a patch. No known workarounds are available.

    Published:Aug 10, 2023
    Last Modified:Nov 21, 2024
    EPS:Aug 10, 2023
    EPSS Score:0.0049
    CVSS Score:4.8

    Affected Products

    Vendor
    Nextcloud
    Product
    User Oidc

    Exploits

    No exploit reference

    Common Attack Pattern Enumeration and Classification (CAPEC)

    CAPEC-90 Reflection Attack in Authentication Protocol

    Related CVEs

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    CVE-2026-45156 (CVSS 8.1) — Nextcloud is an open source content collaboration platform. From versions 0.3.0 to before 3.1.0, 5.0.0 to befo…
    CVE-2024-52512 (CVSS 3.3) — user_oidc app is an OpenID Connect user backend for Nextcloud. A malicious user could send a malformed login l…
    CVE-2024-37886 (CVSS 5.4) — user_oidc app is an OpenID Connect user backend for Nextcloud. An attacker could potentially trick the app int…
    CVE-2024-37312 (CVSS 6.3) — user_oidc app is an OpenID Connect user backend for Nextcloud. Missing access control on the ID4me endpoint al…
    CVE-2023-39954 (CVSS 3.8) — user_oidc provides the OIDC connect user backend for Nextcloud, an open-source cloud platform. Starting in ver…
    CVE-2023-32074 (CVSS 8) — user_oidc app is an OpenID Connect user backend for Nextcloud. Authentication can be broken/bypassed in user_o…
    CVE-2023-28848 (CVSS 4.8) — user_oidc is the OIDC connect user backend for Nextcloud, an open source collaboration platform. A vulnerabili…

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High