External service lookups for a number of protocols were vulnerable to a time-of-check/time-of-use (TOCTOU) weakness, involving the JDK DNS cache. Attackers that were timing DNS cache expiry correctly were able to inject configuration that would bypass existing network deny-lists. Attackers could exploit this weakness to discover the existence of restricted network infrastructure and service availability. Improvements were made to include deny-lists not only during the check of the provided connection data, but also during use. No publicly available exploits are known.

Attackers with access to user accounts can inject arbitrary control characters to SIEVE mail-filter rules. This could be abused to access SIEVE extension that are not allowed by App Suite or to inject rules which would break per-user filter processing, requiring manual cleanup of such rules. We have added sanitization to all mail-filter APIs to avoid forwardning control characters to subsystems. No publicly available exploits are known.

Attackers with access to the "documentconverterws" API were able to inject serialized Java objects, that were not properly checked during deserialization. Access to this API endpoint is restricted to local networks by default. Arbitrary code could be injected that is being executed when processing the request. A check has been introduced to restrict processing of legal and expected classes for this API. We now log a warning in case there are attempts to inject illegal classes. No publicly available exploits are known.

It was possible to call filesystem and network references using the local LibreOffice instance using manipulated ODT documents. Attackers could discover restricted network topology and services as well as including local files with read permissions of the open-xchange system user. This was limited to specific file-types, like images. We have improved existing content filters and validators to avoid including any local resources. No publicly available exploits are known.

When adding an external mail account, processing of POP3 "capabilities" responses are not limited to plausible sizes. Attacker with access to a rogue POP3 service could trigger requests that lead to excessive resource usage and eventually service unavailability. We now limit accepted POP3 server response to reasonable length/size. No publicly available exploits are known.

When adding an external mail account, processing of IMAP "capabilities" responses are not limited to plausible sizes. Attacker with access to a rogue IMAP service could trigger requests that lead to excessive resource usage and eventually service unavailability. We now limit accepted IMAP server response to reasonable length/size. No publicly available exploits are known.

When adding an external mail account, processing of SMTP "capabilities" responses are not limited to plausible sizes. Attacker with access to a rogue SMTP service could trigger requests that lead to excessive resource usage and eventually service unavailability. We now limit accepted SMTP server response to reasonable length/size. No publicly available exploits are known.

IPv4-mapped IPv6 addresses did not get recognized as "local" by the code and a connection attempt is made. Attackers with access to user accounts could use this to bypass existing deny-list functionality and trigger requests to restricted network infrastructure to gain insight about topology and running services. We now respect possible IPV4-mapped IPv6 addresses when checking if contained in a deny-list. No publicly available exploits are known.

Control characters were not removed when exporting user feedback content. This allowed attackers to include unexpected content via user feedback and potentially break the exported data structure. We now drop all control characters that are not whitespace character during the export. No publicly available exploits are known.

Attackers can successfully request arbitrary snippet IDs, including E-Mail signatures of other users within the same context. Signatures of other users could be read even though they are not explicitly shared. We improved permission handling when requesting snippets that are not explicitly shared with other users. No publicly available exploits are known.