Cross-site scripting (XSS) vulnerability in Horde IMP Webmail client before 3.2.8 allows remote attackers to inject arbitrary web script or HTML via the parent's frame page title.

Cross-site scripting (XSS) vulnerability in Horde Mnemo Note Manager before 1.1.4 allows remote attackers to inject arbitrary web script or HTML via the parent's frame page title.

Cross-site scripting (XSS) vulnerability in Horde Vacation module before 2.2.2 allows remote attackers to inject arbitrary web script or HTML via the parent's frame page title.

Cross-site scripting (XSS) vulnerability in Horde Nag Task List Manager before 1.1.3 allows remote attackers to inject arbitrary web script or HTML via the parent's frame page title.

The default installation of Horde 3.0.4 contains an administrative account with a blank password, which allows remote attackers to gain access.

Unspecified cross-site scripting (XSS) vulnerability in Horde before 2.2.9 allows remote attackers to inject arbitrary web script or HTML via "not properly escaped error messages".

Multiple cross-site scripting (XSS) vulnerabilities in Horde before 3.0.7 allow remote attackers to inject arbitrary web script or HTML via the (1) gzip/tar and (2) css MIME viewers, which do not filter or escape dangerous HTML when extracting and displaying attachments.

Horde IMP 4.0.4 and earlier does not sanitize strings containing UTF16 null characters, which allows remote attackers to conduct cross-site scripting (XSS) attacks via UTF16 encoded attachments and strings that will be executed when viewed using Internet Explorer, which ignores the characters.

Horde IMP through 6.2.27, as used with Horde Application Framework through 5.2.23, allows XSS that leads to account takeover via a crafted text/html e-mail message with an onerror attribute (that may use base64-encoded JavaScript code), as exploited in the wild in March 2025.

Disclosure of sensitive information in Horde Groupware

Horde Groupware v5.2.22 has a user enumeration vulnerability that allows an unauthenticated attacker to determine the existence of valid accounts on the system. To exploit the vulnerability, an HTTP request must be sent to ‘/imp/attachment.php’ including the parameters ‘id’ and ‘u’. If the specified user exists, the server will return the download of an empty file; if it does not exist, no download will be initiated, which unequivocally reveals the validity of the user.

Denial of Service was found in Horde_Image 2.x before 2.5.0 via a crafted URL to the "Null" image driver.

In Horde Groupware 5.2.19, there is XSS via the Name field during creation of a new Resource. This can be leveraged for remote code execution after compromising an administrator account, because the CVE-2015-7984 CSRF protection mechanism can then be bypassed.

Remote Code Execution was found in Horde_Image 2.x before 2.5.0 via a crafted GET request. Exploitation requires authentication.

In Horde_Crypt before 2.7.6, as used in Horde Groupware Webmail Edition 5.x through 5.2.17, OS Command Injection can occur if the user has PGP features enabled in the user's preferences, and has enabled the "Should PGP signed messages be automatically verified when viewed?" preference. To exploit this vulnerability, an attacker can send a PGP signed email (that is maliciously crafted) to the Horde user, who then must either view or preview it.

In Horde_Crypt before 2.7.6, as used in Horde Groupware Webmail Edition through 5.2.17, OS Command Injection can occur if the attacker is an authenticated Horde Webmail user, has PGP features enabled in their preferences, and attempts to encrypt an email addressed to a maliciously crafted email address.

A Remote Code Execution vulnerability has been found in the Horde_Image library when using the "Im" backend that utilizes ImageMagick's "convert" utility. It's not exploitable through any Horde application, because the code path to the vulnerability is not used by any Horde code. Custom applications using the Horde_Image library might be affected. This vulnerability affects all versions of Horde_Image from 2.0.0 to 2.5.1, and is fixed in 2.5.2. The problem is missing input validation of the index field in _raw() during construction of an ImageMagick command line.

In Horde Groupware 5.2.19-5.2.22, there is XSS via the URL field in a "Calendar -> New Event" action.

The File Manager (gollem) module 3.0.11 in Horde Groupware 5.2.21 allows remote attackers to bypass Horde authentication for file downloads via a crafted fn parameter that corresponds to the exact filename.

In Horde Groupware 5.2.19 and 5.2.21, there is XSS via the Color field in a Create Task List action.

Cross-site scripting (XSS) vulnerability in the _renderVarInput_number function in horde/framework/Core/lib/Horde/Core/Ui/VarRenderer/Html.php in Horde Groupware before 5.2.12 and Horde Groupware Webmail Edition before 5.2.12 allows remote attackers to inject arbitrary web script or HTML via vectors involving numeric form fields.