The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.17.0 and 5.0.0-alpha.20, there is a signature confusion attack in the HTTPRedirect binding. An attacker with any signed SAMLResponse via the HTTP-Redirect binding can cause the application to accept an unsigned message. Versions 4.17.0 and 5.0.0-alpha.20 contain a fix for the issue.

The remote Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / Pro Realtime 24.04 LTS host has a package installed that is affected by multiple vulnerabilities as referenced in the USN-8770-1 advisory.

    It was discovered that SimpleSAMLphp incorrectly validated cryptographic signatures in XML messages. An     authenticated attacker could possibly use this issue to impersonate users or gain elevated privileges.
    This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2019-3465)

    It was discovered that SimpleSAMLphp incorrectly handled external entities when parsing untrusted XML     documents. A remote attacker could possibly use this issue to obtain sensitive information. This issue did     not affect Ubuntu 24.04 LTS. (CVE-2024-52596)

    It was discovered that SimpleSAMLphp incorrectly verified signatures in SAML messages using the HTTP-     Redirect binding. A remote attacker could possibly use this issue to bypass authentication and impersonate     users. (CVE-2025-27773)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

According to its self-reported version, the Tenable Security Center running on the remote host is version 6.6.0. It is, therefore, affected by multiple vulnerabilities as referenced in the TNS-2025-20 advisory.

  - Symphony process is a module for the Symphony PHP framework which executes commands in sub-processes. On     Windows, when an executable file named `cmd.exe` is located in the current working directory it will be     called by the `Process` class when preparing command arguments, leading to possible hijacking. This issue     has been addressed in release versions 5.4.46, 6.4.14, and 7.1.7. Users are advised to upgrade. There are     no known workarounds for this vulnerability. (CVE-2024-51736)

  - Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Starting     in versions 2.0.0, 5.0.0, and 6.0.0 and prior to versions 4.4.51, 5.4.31, and 6.3.8, some Twig filters in     CodeExtension use `is_safe=html` but don't actually ensure their input is safe. As of versions 4.4.51,     5.4.31, and 6.3.8, Symfony now escapes the output of the affected filters. (CVE-2023-46734)

  - The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.17.0     and 5.0.0-alpha.20, there is a signature confusion attack in the HTTPRedirect binding. An attacker with     any signed SAMLResponse via the HTTP-Redirect binding can cause the application to accept an unsigned     message. Versions 4.17.0 and 5.0.0-alpha.20 contain a fix for the issue. (CVE-2025-27773)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.17.0     and 5.0.0-alpha.20, there is a signature confusion attack in the HTTPRedirect binding. An attacker with     any signed SAMLResponse via the HTTP-Redirect binding can cause the application to accept an unsigned     message. Versions 4.17.0 and 5.0.0-alpha.20 contain a fix for the issue. (CVE-2025-27773)

Note that Nessus relies on the presence of the package as reported by the vendor.

The remote Debian 11 host has a package installed that is affected by a vulnerability as referenced in the dla-4161 advisory.

    -------------------------------------------------------------------------     Debian LTS Advisory DLA-4161-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                         Tobias Frost     May 09, 2025                                  https://wiki.debian.org/LTS
    -------------------------------------------------------------------------

    Package        : simplesamlphp     Version        : 1.19.0-1+deb11u2     CVE ID         : CVE-2025-27773     Debian Bug     : 1100595

    A vulnerability has been discovered in SimpleSAMLphp, a framework for     authentication, primarily via the SAML protocol.

    CVE-2025-27773

        The SimpleSAMLphp SAML2 library is a PHP library for SAML2         related functionality. Prior to versions 4.17.0 and 5.0.0-alpha.20,         there is a signature confusion attack in the HTTPRedirect binding.
        An attacker with any signed SAMLResponse via the HTTP-Redirect         binding can cause the application to accept an unsigned message.
        Versions 4.17.0 and 5.0.0-alpha.20 contain a fix for the issue.

    For Debian 11 bullseye, this problem has been fixed in version     1.19.0-1+deb11u2.

    We recommend that you upgrade your simplesamlphp packages.

    For the detailed security status of simplesamlphp please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/simplesamlphp

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS     Attachment:
    signature.asc     Description: PGP signature

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.17.0
    and 5.0.0-alpha.20, there is a signature confusion attack in the HTTPRedirect binding. An attacker with
    any signed SAMLResponse via the HTTP-Redirect binding can cause the application to accept an unsigned
    message. Versions 4.17.0 and 5.0.0-alpha.20 contain a fix for the issue. (CVE-2025-27773)

ID	Name	Product	Family	Type	Severity
346237	Ubuntu 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / Pro Realtime 24.04 LTS : SimpleSAMLphp vulnerabilities (USN-8770-1)	Nessus	Ubuntu Local Security Checks	Local	high
266393	Tenable Security Center Multiple Vulnerabilities (TNS-2025-20)	Nessus	Misc.	Combined	high
257036	Linux Distros Unpatched Vulnerability : CVE-2025-27773	Nessus	Misc.	Local	high
235669	Debian dla-4161 : simplesamlphp - security update	Nessus	Debian Local Security Checks	Local	high
421101	SCA: security update for simplesamlphp/saml2, simplesamlphp/saml2-legacy (GHSA-46r4-f8gj-xg56)	Tenable Cloud Security	SCA Checks	Local	high
421101	SCA: security update for simplesamlphp/saml2, simplesamlphp/saml2-legacy (GHSA-46r4-f8gj-xg56)	Tenable Self-Hosted Container Security	SCA Checks	Local	high

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