mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. When mod_auth_openidc versions prior to 2.4.9 are configured to use an unencrypted Redis cache (`OIDCCacheEncrypt off`, `OIDCSessionType server-cache`, `OIDCCacheType redis`), `mod_auth_openidc` wrongly performed argument interpolation before passing Redis requests to `hiredis`, which would perform it again and lead to an uncontrolled format string bug. Initial assessment shows that this bug does not appear to allow gaining arbitrary code execution, but can reliably provoke a denial of service by repeatedly crashing the Apache workers. This bug has been corrected in version 2.4.9 by performing argument interpolation only once, using the `hiredis` API. As a workaround, this vulnerability can be mitigated by setting `OIDCCacheEncrypt` to `on`, as cache keys are cryptographically hashed before use when this option is enabled.

The remote SUSE Linux SLES15 / SLES_SAP15 / openSUSE 15 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2025:4532-1 advisory.

    - Update to 2.4.17.1 (bsc#1248806 / PED-14130).
    - Remove many patches, as they've been merged upstream.

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

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.

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. When     mod_auth_openidc versions prior to 2.4.9 are configured to use an unencrypted Redis cache     (`OIDCCacheEncrypt off`, `OIDCSessionType server-cache`, `OIDCCacheType redis`), `mod_auth_openidc`     wrongly performed argument interpolation before passing Redis requests to `hiredis`, which would perform     it again and lead to an uncontrolled format string bug. Initial assessment shows that this bug does not     appear to allow gaining arbitrary code execution, but can reliably provoke a denial of service by     repeatedly crashing the Apache workers. This bug has been corrected in version 2.4.9 by performing     argument interpolation only once, using the `hiredis` API. As a workaround, this vulnerability can be     mitigated by setting `OIDCCacheEncrypt` to `on`, as cache keys are cryptographically hashed before use     when this option is enabled. (CVE-2021-32785)

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

The remote Debian 10 host has a package installed that is affected by multiple vulnerabilities as referenced in the dla-3409 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-3409-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                          Adrian Bunk     April 30, 2023                                https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : libapache2-mod-auth-openidc     Version        : 2.3.10.2-1+deb10u2     CVE ID         : CVE-2019-20479 CVE-2021-32785 CVE-2021-32786 CVE-2021-32791                      CVE-2021-32792 CVE-2023-28625     Debian Bug     : 991580 991581 991582 991583 1033916

    Several vulnerabilities were fixed in libapache2-mod-auth-openidc,     an OpenID Connect Relying Party implementation for Apache.

    CVE-2019-20479

        Insufficient validatation of URLs beginning with a slash and backslash.

    CVE-2021-32785

        Crash when using an unencrypted Redis cache.

    CVE-2021-32786

        Open Redirect vulnerability in the logout functionality.

    CVE-2021-32791

        AES GCM encryption in used static IV and AAD.

    CVE-2021-32792

        XSS vulnerability when using OIDCPreservePost.

    CVE-2023-28625

        NULL pointer dereference with OIDCStripCookies.

    For Debian 10 buster, these problems have been fixed in version     2.3.10.2-1+deb10u2.

    We recommend that you upgrade your libapache2-mod-auth-openidc packages.

    For the detailed security status of libapache2-mod-auth-openidc please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/libapache2-mod-auth-openidc

    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

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

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

The remote SUSE Linux SLES12 / SLES_SAP12 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2021:3352-1 advisory.

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. When     mod_auth_openidc versions prior to 2.4.9 are configured to use an unencrypted Redis cache     (`OIDCCacheEncrypt off`, `OIDCSessionType server-cache`, `OIDCCacheType redis`), `mod_auth_openidc`     wrongly performed argument interpolation before passing Redis requests to `hiredis`, which would perform     it again and lead to an uncontrolled format string bug. Initial assessment shows that this bug does not     appear to allow gaining arbitrary code execution, but can reliably provoke a denial of service by     repeatedly crashing the Apache workers. This bug has been corrected in version 2.4.9 by performing     argument interpolation only once, using the `hiredis` API. As a workaround, this vulnerability can be     mitigated by setting `OIDCCacheEncrypt` to `on`, as cache keys are cryptographically hashed before use     when this option is enabled. (CVE-2021-32785)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions     prior to 2.4.9, `oidc_validate_redirect_url()` does not parse URLs the same way as most browsers do. As a     result, this function can be bypassed and leads to an Open Redirect vulnerability in the logout     functionality. This bug has been fixed in version 2.4.9 by replacing any backslash of the URL to redirect     with slashes to address a particular breaking change between the different specifications (RFC2396 /     RFC3986 and WHATWG). As a workaround, this vulnerability can be mitigated by configuring     `mod_auth_openidc` to only allow redirection whose destination matches a given regular expression.
    (CVE-2021-32786)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In     mod_auth_openidc before version 2.4.9, the AES GCM encryption in mod_auth_openidc uses a static IV and     AAD. It is important to fix because this creates a static nonce and since aes-gcm is a stream cipher, this     can lead to known cryptographic issues, since the same key is being reused. From 2.4.9 onwards this has     been patched to use dynamic values through usage of cjose AES encryption routines. (CVE-2021-32791)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In     mod_auth_openidc before version 2.4.9, there is an XSS vulnerability in when using `OIDCPreservePost On`.
    (CVE-2021-32792)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions     prior to 2.4.9.4, the 3rd-party init SSO functionality of mod_auth_openidc was reported to be vulnerable     to an open redirect attack by supplying a crafted URL in the `target_link_uri` parameter. A patch in     version 2.4.9.4 made it so that the `OIDCRedirectURLsAllowed` setting must be applied to the     `target_link_uri` parameter. There are no known workarounds aside from upgrading to a patched version.
    (CVE-2021-39191)

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

The remote SUSE Linux SUSE15 host has a package installed that is affected by multiple vulnerabilities as referenced in the openSUSE-SU-2021:1277-1 advisory.

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. When     mod_auth_openidc versions prior to 2.4.9 are configured to use an unencrypted Redis cache     (`OIDCCacheEncrypt off`, `OIDCSessionType server-cache`, `OIDCCacheType redis`), `mod_auth_openidc`     wrongly performed argument interpolation before passing Redis requests to `hiredis`, which would perform     it again and lead to an uncontrolled format string bug. Initial assessment shows that this bug does not     appear to allow gaining arbitrary code execution, but can reliably provoke a denial of service by     repeatedly crashing the Apache workers. This bug has been corrected in version 2.4.9 by performing     argument interpolation only once, using the `hiredis` API. As a workaround, this vulnerability can be     mitigated by setting `OIDCCacheEncrypt` to `on`, as cache keys are cryptographically hashed before use     when this option is enabled. (CVE-2021-32785)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions     prior to 2.4.9, `oidc_validate_redirect_url()` does not parse URLs the same way as most browsers do. As a     result, this function can be bypassed and leads to an Open Redirect vulnerability in the logout     functionality. This bug has been fixed in version 2.4.9 by replacing any backslash of the URL to redirect     with slashes to address a particular breaking change between the different specifications (RFC2396 /     RFC3986 and WHATWG). As a workaround, this vulnerability can be mitigated by configuring     `mod_auth_openidc` to only allow redirection whose destination matches a given regular expression.
    (CVE-2021-32786)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In     mod_auth_openidc before version 2.4.9, the AES GCM encryption in mod_auth_openidc uses a static IV and     AAD. It is important to fix because this creates a static nonce and since aes-gcm is a stream cipher, this     can lead to known cryptographic issues, since the same key is being reused. From 2.4.9 onwards this has     been patched to use dynamic values through usage of cjose AES encryption routines. (CVE-2021-32791)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In     mod_auth_openidc before version 2.4.9, there is an XSS vulnerability in when using `OIDCPreservePost On`.
    (CVE-2021-32792)

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

The remote SUSE Linux SLES15 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2021:3020-1 advisory.

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. When     mod_auth_openidc versions prior to 2.4.9 are configured to use an unencrypted Redis cache     (`OIDCCacheEncrypt off`, `OIDCSessionType server-cache`, `OIDCCacheType redis`), `mod_auth_openidc`     wrongly performed argument interpolation before passing Redis requests to `hiredis`, which would perform     it again and lead to an uncontrolled format string bug. Initial assessment shows that this bug does not     appear to allow gaining arbitrary code execution, but can reliably provoke a denial of service by     repeatedly crashing the Apache workers. This bug has been corrected in version 2.4.9 by performing     argument interpolation only once, using the `hiredis` API. As a workaround, this vulnerability can be     mitigated by setting `OIDCCacheEncrypt` to `on`, as cache keys are cryptographically hashed before use     when this option is enabled. (CVE-2021-32785)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions     prior to 2.4.9, `oidc_validate_redirect_url()` does not parse URLs the same way as most browsers do. As a     result, this function can be bypassed and leads to an Open Redirect vulnerability in the logout     functionality. This bug has been fixed in version 2.4.9 by replacing any backslash of the URL to redirect     with slashes to address a particular breaking change between the different specifications (RFC2396 /     RFC3986 and WHATWG). As a workaround, this vulnerability can be mitigated by configuring     `mod_auth_openidc` to only allow redirection whose destination matches a given regular expression.
    (CVE-2021-32786)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In     mod_auth_openidc before version 2.4.9, the AES GCM encryption in mod_auth_openidc uses a static IV and     AAD. It is important to fix because this creates a static nonce and since aes-gcm is a stream cipher, this     can lead to known cryptographic issues, since the same key is being reused. From 2.4.9 onwards this has     been patched to use dynamic values through usage of cjose AES encryption routines. (CVE-2021-32791)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In     mod_auth_openidc before version 2.4.9, there is an XSS vulnerability in when using `OIDCPreservePost On`.
    (CVE-2021-32792)

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

The remote SUSE Linux SUSE15 host has a package installed that is affected by multiple vulnerabilities as referenced in the openSUSE-SU-2021:3020-1 advisory.

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. When     mod_auth_openidc versions prior to 2.4.9 are configured to use an unencrypted Redis cache     (`OIDCCacheEncrypt off`, `OIDCSessionType server-cache`, `OIDCCacheType redis`), `mod_auth_openidc`     wrongly performed argument interpolation before passing Redis requests to `hiredis`, which would perform     it again and lead to an uncontrolled format string bug. Initial assessment shows that this bug does not     appear to allow gaining arbitrary code execution, but can reliably provoke a denial of service by     repeatedly crashing the Apache workers. This bug has been corrected in version 2.4.9 by performing     argument interpolation only once, using the `hiredis` API. As a workaround, this vulnerability can be     mitigated by setting `OIDCCacheEncrypt` to `on`, as cache keys are cryptographically hashed before use     when this option is enabled. (CVE-2021-32785)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In versions     prior to 2.4.9, `oidc_validate_redirect_url()` does not parse URLs the same way as most browsers do. As a     result, this function can be bypassed and leads to an Open Redirect vulnerability in the logout     functionality. This bug has been fixed in version 2.4.9 by replacing any backslash of the URL to redirect     with slashes to address a particular breaking change between the different specifications (RFC2396 /     RFC3986 and WHATWG). As a workaround, this vulnerability can be mitigated by configuring     `mod_auth_openidc` to only allow redirection whose destination matches a given regular expression.
    (CVE-2021-32786)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In     mod_auth_openidc before version 2.4.9, the AES GCM encryption in mod_auth_openidc uses a static IV and     AAD. It is important to fix because this creates a static nonce and since aes-gcm is a stream cipher, this     can lead to known cryptographic issues, since the same key is being reused. From 2.4.9 onwards this has     been patched to use dynamic values through usage of cjose AES encryption routines. (CVE-2021-32791)

  - mod_auth_openidc is an authentication/authorization module for the Apache 2.x HTTP server that functions     as an OpenID Connect Relying Party, authenticating users against an OpenID Connect Provider. In     mod_auth_openidc before version 2.4.9, there is an XSS vulnerability in when using `OIDCPreservePost On`.
    (CVE-2021-32792)

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

ID	Name	Product	Family	Severity
280142	SUSE SLES15 / openSUSE 15 Security Update : apache2-mod_auth_openidc (SUSE-SU-2025:4532-1)	Nessus	SuSE Local Security Checks	high
252443	Linux Distros Unpatched Vulnerability : CVE-2021-32785	Nessus	Misc.	high
174970	Debian dla-3409 : libapache2-mod-auth-openidc - security update	Nessus	Debian Local Security Checks	medium
154089	SUSE SLES12 Security Update : apache2-mod_auth_openidc (SUSE-SU-2021:3352-1)	Nessus	SuSE Local Security Checks	medium
153452	openSUSE 15 Security Update : apache2-mod_auth_openidc (openSUSE-SU-2021:1277-1)	Nessus	SuSE Local Security Checks	medium
153248	SUSE SLES15 Security Update : apache2-mod_auth_openidc (SUSE-SU-2021:3020-1)	Nessus	SuSE Local Security Checks	medium
153244	openSUSE 15 Security Update : apache2-mod_auth_openidc (openSUSE-SU-2021:3020-1)	Nessus	SuSE Local Security Checks	medium

Detections

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CVE-2021-32785

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Tenable Plugins

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