An attacker might be able to trigger an out-of-bounds read by sending a crafted DNS response packet, when custom Lua code uses newDNSPacketOverlay to parse DNS packets. The out-of-bounds read might trigger a crash, leading to a denial of service, or access unrelated memory, leading to potential information disclosure.

When the internal webserver is enabled (default is disabled), an attacker might be able to trick an administrator logged to the dashboard into visiting a malicious website and extract information about the running configuration from the dashboard. The root cause of the issue is a misconfiguration of the Cross-Origin Resource Sharing (CORS) policy.

An attacker might be able to inject HTML content into the internal web dashboard by sending crafted DNS queries to a DNSdist instance where domain-based dynamic rules have been enabled via either DynBlockRulesGroup:setSuffixMatchRule or DynBlockRulesGroup:setSuffixMatchRuleFFI.

If auth_username_chars is empty, it is possible to inject arbitrary LDAP filter to Dovecot's LDAP authentication. This leads to potentially bypassing restrictions and allows probing of LDAP structure. Do not clear out auth_username_chars, or install fixed version. No publicly available exploits are known.

A mail message containing excessive amount of RFC 2231 MIME parameters causes LMTP to use too much CPU. A suitably formatted mail message causes mail delivery process to consume large amounts of CPU time. Use MTA capabilities to limit RFC 2231 MIME parameters in mail messages, or upgrade to fixed version where the processing is limited. No publicly available exploits are known.

Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory. Attacker can force managesieve-login to be unavailable by repeatedly crashing the process. Protect access to managesieve protocol, or install fixed version. No publicly available exploits are known.

Sending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage. Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time periods by not sending the command ending LF. So attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Install fixed version, there is no other remediation. No publicly available exploits are known.

Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack. An attacker can use this to determine the configured credentials. Figuring out the credential will lead into full access to the affected component. Limit access to the doveadm http service port, install fixed version. No publicly available exploits are known.

Dovecot OTP authentication is vulnerable to replay attack under specific conditions. If auth cache is enabled, and username is altered in passdb, then OTP credentials can be cached so that same OTP reply is valid. An attacker able to observe an OTP exchange is able to log in as the user. If authentication happens over unsecure connection, switch to SCRAM protocol. Alternatively ensure the communcations are secured, and if possible switch to OAUTH2 or SCRAM. No publicly available exploits are known.

Dovecot SQL based authentication can be bypassed when auth_username_chars is cleared by admin. This vulnerability allows bypassing authentication for any user and user enumeration. Do not clear auth_username_chars. If this is not possible, install latest fixed version. No publicly available exploits are known.

When dovecot has been configured to use per-domain passwd files, and they are placed one path component above /etc, or slash has been added to allowed characters, path traversal can happen if the domain component is directory partial. This allows inadvertently reading /etc/passwd (or some other path which ends with passwd). If this file contains passwords, it can be used to authenticate wrongly, or if this is userdb, it can unexpectly make system users appear valid users. Upgrade to fixed version, or use different authentication scheme that does not rely on paths. Alternatively you can also ensure that the per-domain passwd files are in some other location, such as /etc/dovecot/auth/%d. No publicly available exploits are known.

ManageSieve AUTHENTICATE command crashes when using literal as SASL initial response. This can be used to crash ManageSieve service repeatedly, making it unavailable for other users. Control access to ManageSieve port, or disable the service if it's not needed. Alternatively upgrade to a fixed version. No publicly available exploits are known.

Dovecot has provided a script to use for attachment to text conversion. This script unsafely handles zip-style attachments. Attacker can use specially crafted OOXML documents to cause unintended files on the system to be indexed and subsequently ending up in FTS indexes. Do not use the provided script, instead, use something else like FTS tika. No publicly available exploits are known.

When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No publicly available exploits are known.

Crafted delegations or IP fragments can poison cached delegations in Recursor.

Crafted delegations or IP fragments can poison cached delegations in Recursor.

Crafted zones can lead to increased incoming network traffic.

Crafted zones can lead to increased resource usage and crafted CNAME chains can lead to cache poisoning in Recursor.

An attacker can trigger an assertion failure by requesting crafted DNS records, waiting for them to be inserted into the records cache, then send a query with qtype set to ANY.

An attacker can trigger the removal of cached records by sending a NOTIFY query over TCP.

Malicious content uploaded as file can be used to execute script code when following attacker-controlled links. Unintended actions can be executed in the context of the users account, including exfiltration of sensitive information. Please deploy the provided updates and patch releases. No publicly available exploits are known

Malicious e-mail content can be used to execute script code. Unintended actions can be executed in the context of the users account, including exfiltration of sensitive information. Sanitization has been updated to avoid such bypasses. No publicly available exploits are known

Malicious content at office documents can be used to inject script code when editing a document. Unintended actions can be executed in the context of the users account, including exfiltration of sensitive information. Please deploy the provided updates and patch releases. No publicly available exploits are known

Malicious content uploaded as file can be used to execute script code when following attacker-controlled links. Unintended actions can be executed in the context of the users account, including exfiltration of sensitive information. Please deploy the provided updates and patch releases. No publicly available exploits are known

When cache is enabled, some passdb/userdb drivers incorrectly cache all users with same cache key, causing wrong cached information to be used for these users. After cached login, all subsequent logins are for same user. Install fixed version or disable caching either globally or for the impacted passdb/userdb drivers. No publicly available exploits are known.

Malicious content from E-Mail can be used to perform a redressing attack. Users can be tricked to perform unintended actions or provide sensitive information to a third party which would enable further threats. Attribute values containing HTML fragments are now denied by the sanitization procedure. No publicly available exploits are known

Malicious or unintentional API requests can be used to add significant amount of data to caches. Caches may evict information that is required to operate the web frontend, which leads to unavailability of the component. Please deploy the provided updates and patch releases. No publicly available exploits are known

In some circumstances, when DNSdist is configured to use the nghttp2 library to process incoming DNS over HTTPS queries, an attacker might be able to cause a denial of service by crafting a DoH exchange that triggers an unbounded I/O read loop, causing an unexpected consumption of CPU resources.

An attacker spoofing answers to ECS enabled requests sent out by the Recursor has a chance of success higher than non-ECS enabled queries. The updated version include various mitigations against spoofing attempts of ECS enabled queries by chaining ECS enabled requests and enforcing stricter validation of the received answers. The most strict mitigation done when the new setting outgoing.edns_subnet_harden (old style name edns-subnet-harden) is enabled.

In some circumstances, when DNSdist is configured to allow an unlimited number of queries on a single, incoming TCP connection from a client, an attacker can cause a denial of service by crafting a TCP exchange that triggers an exhaustion of the stack and a crash of DNSdist, causing a denial of service. The remedy is: upgrade to the patched 1.9.10 version. A workaround is to restrict the maximum number of queries on incoming TCP connections to a safe value, like 50, via the setMaxTCPQueriesPerConnection setting. We would like to thank Renaud Allard for bringing this issue to our attention.

When DNSdist is configured to provide DoH via the nghttp2 provider, an attacker can cause a denial of service by crafting a DoH exchange that triggers an illegal memory access (double-free) and crash of DNSdist, causing a denial of service. The remedy is: upgrade to the patched 1.9.9 version. A workaround is to temporarily switch to the h2o provider until DNSdist has been upgraded to a fixed version. We would like to thank Charles Howes for bringing this issue to our attention.

An attacker can publish a zone containing specific Resource Record Sets. Processing and caching results for these sets can lead to an illegal memory accesses and crash of the Recursor, causing a denial of service. The remedy is: upgrade to the patched 5.2.1 version. We would like to thank Volodymyr Ilyin for bringing this issue to our attention.

An attacker can publish a zone containing specific Resource Record Sets. Repeatedly processing and caching results for these sets can lead to a denial of service.

Very large headers can cause resource exhaustion when parsing message. The message-parser normally reads reasonably sized chunks of the message. However, when it feeds them to message-header-parser, it starts building up "full_value" buffer out of the smaller chunks. The full_value buffer has no size limit, so large headers can cause large memory usage. It doesn't matter whether it's a single long header line, or a single header split into multiple lines. This bug exists in all Dovecot versions. Incoming mails typically have some size limits set by MTA, so even largest possible header size may still fit into Dovecot's vsz_limit. So attackers probably can't DoS a victim user this way. A user could APPEND larger mails though, allowing them to DoS themselves (although maybe cause some memory issues for the backend in general). One can implement restrictions on headers on MTA component preceding Dovecot. No publicly available exploits are known.

Having a large number of address headers (From, To, Cc, Bcc, etc.) becomes excessively CPU intensive. With 100k header lines CPU usage is already 12 seconds, and in a production environment we observed 500k header lines taking 18 minutes to parse. Since this can be triggered by external actors sending emails to a victim, this is a security issue. An external attacker can send specially crafted messages that consume target system resources and cause outage. One can implement restrictions on address headers on MTA component preceding Dovecot. No publicly available exploits are known.

Dovecot accepts dot LF DOT LF symbol as end of DATA command. RFC requires that it should always be CR LF DOT CR LF. This causes Dovecot to convert single mail with LF DOT LF in middle, into two emails when relaying to SMTP. Dovecot will split mail with LF DOT LF into two mails. Upgrade to latest released version. No publicly available exploits are known.

Module savepoints could be abused to inject references to malicious code delivered through the same domain. Attackers could perform malicious API requests or extract information from the users account. Exploiting this vulnerability requires temporary access to an account or successful social engineering to make a user follow a prepared link to a malicious account. Please deploy the provided updates and patch releases. The savepoint module path has been restricted to modules that provide the feature, excluding any arbitrary or non-existing modules. No publicly available exploits are known.

When incoming DNS over HTTPS support is enabled using the nghttp2 provider, and queries are routed to a tcp-only or DNS over TLS backend, an attacker can trigger an assertion failure in DNSdist by sending a request for a zone transfer (AXFR or IXFR) over DNS over HTTPS, causing the process to stop and thus leading to a Denial of Service. DNS over HTTPS is not enabled by default, and backends are using plain DNS (Do53) by default.

E-Mails exported as PDF were stored in a cache that did not consider specific session information for the related user account. Users of the same service node could access other users E-Mails in case they were exported as PDF for a brief moment until caches were cleared. Successful exploitation requires good timing and modification of multiple request parameters. Please deploy the provided updates and patch releases. The cache for PDF exports now takes user session information into consideration when performing authorization decisions. No publicly available exploits are known.

Maliciously crafted E-Mail attachment names could be used to temporarily execute script code in the context of the users browser session. Common user interaction is required for the vulnerability to trigger. Attackers could perform malicious API requests or extract information from the users account. Please deploy the provided updates and patch releases. We now use safer methods of handling external content when embedding attachment information to the web interface. No publicly available exploits are known.

Content-ID based embedding of resources in E-Mails could be abused to trigger client-side script code when using the "show more" option. Attackers could perform malicious API requests or extract information from the users account. Exploiting the vulnerability requires user interaction. Please deploy the provided updates and patch releases. CID replacement has been hardened to omit invalid identifiers. No publicly available exploits are known.

E-Mail containing malicious display-name information could trigger client-side script execution when using specific mobile devices. Attackers could perform malicious API requests or extract information from the users account. Please deploy the provided updates and patch releases. We now use safer methods of handling external content when embedding displayname information to the web interface. No publicly available exploits are known.

A crafted response from an upstream server the recursor has been configured to forward-recurse to can cause a Denial of Service in the Recursor. The default configuration of the Recursor does not use recursive forwarding and is not affected.

RSS feeds that contain malicious data- attributes could be abused to inject script code to a users browser session when reading compromised RSS feeds or successfully luring users to compromised accounts. Attackers could perform malicious API requests or extract information from the users account. Please deploy the provided updates and patch releases. Potentially malicious attributes now get removed from external RSS content. No publicly available exploits are known.

Upsell advertisement information of an account can be manipulated to execute script code in the context of the users browser session. To exploit this an attacker would require temporary access to a users account or an successful social engineering attack to lure users to maliciously configured accounts. Attackers could perform malicious API requests or extract information from the users account. Please deploy the provided updates and patch releases. Sanitization of user-defined upsell content has been improved. No publicly available exploits are known.

Upsell shop information of an account can be manipulated to execute script code in the context of the users browser session. To exploit this an attacker would require temporary access to a users account or an successful social engineering attack to lure users to maliciously configured accounts. Attackers could perform malicious API requests or extract information from the users account. Please deploy the provided updates and patch releases. Sanitization of user-defined upsell content has been improved. No publicly available exploits are known.

Embedded content references at tasks could be used to temporarily execute script code in the context of the users browser session. To exploit this an attacker would require temporary access to the users account, access to another account within the same context or an successful social engineering attack to make users import external content. Attackers could perform malicious API requests or extract information from the users account. Please deploy the provided updates and patch releases. Sanitization of user-generated content has been improved. No publicly available exploits are known.

References to the "app loader" functionality could contain redirects to unexpected locations. Attackers could forge app references that bypass existing safeguards to inject malicious script code. Please deploy the provided updates and patch releases. References to apps are now controlled more strict to avoid relative references. No publicly available exploits are known.

Processing of user-defined mail search expressions is not limited. Availability of OX App Suite could be reduced due to high processing load. Please deploy the provided updates and patch releases. Processing time of mail search expressions now gets monitored, and the related request is terminated if a resource threshold is reached. No publicly available exploits are known.

Processing time of drive search expressions now gets monitored, and the related request is terminated if a resource threshold is reached. Availability of OX App Suite could be reduced due to high processing load. Please deploy the provided updates and patch releases. Processing of user-defined drive search expressions is not limited No publicly available exploits are known.