Horde IMP's AppleDouble MIME viewer writes an attacker-controlled attachment name into an HTML status block without escaping it. In lib/Mime/Viewer/Appledouble.php, IMPrender() obtains the name of the data part with IMPContents::getPartName(), which returns the MIME part's own name parameter as supplied by the message, and passes it through sprintf into the text of an IMPMimeStatus object. IMPMimeStatus::toString() concatenates each text entry directly into the surrounding table markup, so the value reaches the rendered page verbatim. A message crafted as multipart/appledouble whose data part carries markup in its name parameter therefore executes script in the context of any user who views it, and the payload persists in the mailbox. Exploitation requires no account on the target system, only the ability to send mail to a user. Version 7.2.0 escapes the value with htmlspecialchars(). The researcher additionally chains this flaw with the arbitrary file read of CVE-2026-58451, and reports that script running in an administrator's session can reach an application code-execution path.

Horde Virtual File System (VFS) API before 3.0.1 contains an OS command injection vulnerability in the HordeVfsSmb driver where the escapeShellCommand() method fails to sanitize command substitution sequences, allowing authenticated attackers to inject arbitrary shell commands through user-controlled filenames. Attackers can supply malicious filenames containing unescaped command substitution payloads through operations such as file upload, folder creation, rename, or deletion, which are interpolated into a double-quoted shell context and executed via procopen() through /bin/sh -c before smbclient runs, resulting in arbitrary command execution on the underlying system.

Horde IMP before 7.0.1 contains a path traversal vulnerability in lib/Compose.php that allows authenticated attackers to read arbitrary files from the server filesystem by embedding traversal sequences after a CKEditor path prefix in img src URLs. Attackers can bypass the stripos() prefix validation by appending sequences such as traversal segments after the matching prefix, causing filegetcontents() to read sensitive files whose contents are then exfiltrated as MIME parts in outgoing email; unauthenticated exploitation is also achievable via CSRF against an active authenticated session.

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.

This vulnerability allows remote attackers to create arbitrary files on affected installations of Horde Groupware Webmail Edition 5.2.22. Authentication is required to exploit this vulnerability. The specific flaw exists within add.php. The issue results from the lack of proper validation of user-supplied data, which can allow the upload of arbitrary files. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of the www-data user. Was ZDI-CAN-10125.

This vulnerability allows remote attackers to execute local PHP files on affected installations of Horde Groupware Webmail Edition 5.2.22. Authentication is required to exploit this vulnerability. The specific flaw exists within edit.php. When parsing the params[template] parameter, the process does not properly validate a user-supplied path prior to using it in file operations. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of the www-data user. Was ZDI-CAN-10469.

Horde Groupware Webmail Edition 5.2.22 allows injection of arbitrary PHP code via CSV data, leading to remote code execution.

In HordeCrypt 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 HordeCrypt 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.

The framework/Util/lib/Horde/Variables.php script in the Util library in Horde before 5.1.1 allows remote attackers to conduct object injection attacks and execute arbitrary PHP code via a crafted serialized object in the formvars form.

Cross-site scripting (XSS) vulnerability in the XSS filter (framework/TextFilter/Filter/xss.php) in Horde Application Framework 3.2.2 and 3.3, when Internet Explorer is being used, allows remote attackers to inject arbitrary web script or HTML via unknown vectors related to style attributes.

Horde before 2.2.4 allows remote malicious web sites to steal session IDs and read or create arbitrary email by stealing the ID from a referrer URL.

Multiple SQL injection vulnerabilities in IMP 2.2.8 and earlier allow remote attackers to perform unauthorized database activities and possibly gain privileges via certain database functions such as checkprefs() in db.pgsql, as demonstrated using mailbox.php3.

Horde IMP 2.2.7 allows remote attackers to obtain the full web root pathname via an HTTP request for (1) poppassd.php3, (2) login.php3?reason=chpass2, (3) spelling.php3, and (4) ldap.search.php3?ldapserv=nonsense which leaks the information in error messages.

Cross-site scripting (XSS) vulnerability in Horde Internet Mail Program (IMP) before 5.0.22, as used in Horde Groupware Webmail Edition before 4.0.9, allows remote attackers to inject arbitrary web script or HTML via a crafted SVG image attachment, a different vulnerability than CVE-2012-5565.

Cross-site scripting (XSS) vulnerability in js/compose-dimp.js in Horde Internet Mail Program (IMP) before 5.0.24, as used in Horde Groupware Webmail Edition before 4.0.9, allows remote attackers to inject arbitrary web script or HTML via a crafted name for an attached file, related to the dynamic view.

Multiple cross-site scripting (XSS) vulnerabilities in Horde Kronolith Calendar Application H4 before 3.0.17, as used in Horde Groupware Webmail Edition before 4.0.8, allow remote attackers to inject arbitrary web script or HTML via the (1) tasks view or (2) search view.

A cross-site scripting (XSS) flaw was found in the way Kronolith, the Horde calendar application, sanitized content of certain event location parameters passed to month, monthlist and prevmonthlist application fields. A remote attacker could provide a specially-crafted URL that, when visited would lead to arbitrary HTML or webscript execution.

References: [1] http://lists.horde.org/archives/announce/2012/000836.html [2] https://github.com/horde/horde/blob/d3dda2d47fad7eb128a0091e732cded0c2601009/kronolith/docs/CHANGES

Refevant upstream patch: [3] http://git.horde.org/horde-git/-/commit/d865c564beb6e98532880aa51a04a79f3311cd1e

Horde IMP 4.3.6 and earlier does not request that the web browser avoid DNS prefetching of domain names contained in e-mail messages, which makes it easier for remote attackers to determine the network location of the webmail user by logging DNS requests.

procmail in Ingo H3 before 1.1.2 Horde module allows remote authenticated users to execute arbitrary commands via shell metacharacters in the mailbox destination of a filter rule.

Directory traversal vulnerability in lib/FBView.php in Horde Kronolith H3 before 2.0.7 and 2.1.x before 2.1.4 allows remote attackers to include arbitrary files and execute PHP code via a .. (dot dot) sequence in the view parameter.

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.

DISPUTED Multiple cross-site scripting (XSS) vulnerabilities in Horde Groupware Webmail 1.0 allow remote authenticated users to inject arbitrary web script or HTML via unspecified vectors in (1) imp/search.php and (2) ingo/rule.php. NOTE: this issue has been disputed by the vendor, noting that the search.php issue was resolved in CVE-2006-4255, and attackers can only use rule.php to inject XSS into their own pages.

lib/Horde/Mime/Viewer/Ooo.php in Horde MimeViewer before 2.2.4 allows XSS via an OpenOffice document, leading to account takeover in Horde Groupware Webmail Edition. This occurs after XSLT rendering.

Horde Groupware Webmail Edition through 5.2.22 allows a reflection injection attack through which an attacker can instantiate a driver class. This then leads to arbitrary deserialization of PHP objects.

Multiple cross-site scripting (XSS) vulnerabilities in Horde Internet Mail Program (IMP) before 6.1.8, as used in Horde Groupware Webmail Edition before 5.1.5, allow remote attackers to inject arbitrary web script or HTML via an unspecified flag in the basic (1) mailbox or (2) message view.

Cross-site scripting (XSS) vulnerability in HordeForm in Horde Groupware Webmail Edition before 4.0.6 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors, related to email verification. NOTE: Some of these details are obtained from third party information.

Multiple cross-site scripting (XSS) vulnerabilities in fetchmailprefs.php in Horde IMP before 4.3.8, and Horde Groupware Webmail Edition before 1.2.7, allow remote attackers to inject arbitrary web script or HTML via the (1) username (aka fmusername), (2) password (aka fmpassword), or (3) server (aka fmserver) field in a fetchmailprefssave action, related to the Fetchmail configuration, a different issue than CVE-2010-3695. NOTE: some of these details are obtained from third party information.

Multiple cross-site scripting (XSS) vulnerabilities in Horde Internet Mail Program (IMP) before 6.1.8, as used in Horde Groupware Webmail Edition before 5.1.5, allow remote attackers to inject arbitrary web script or HTML via (1) unspecified flags or (2) a mailbox name in the dynamic mailbox view.

TextFilter/lib/Horde/Text/Filter/Xss.php in Horde Application Framework before 3.3.6, Horde Groupware before 1.2.5, and Horde Groupware Webmail Edition before 1.2.5 does not properly handle data: URIs, which allows remote attackers to conduct cross-site scripting (XSS) attacks via data:text/html values for the HREF attribute of an A element in an HTML e-mail message. NOTE: the vendor states that the issue is caused by "an XSS vulnerability in Firefox browsers."