{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata. Fed continuously.","feed_url":"https://feed.craftedsignal.io/tags/webmail/feed.json","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cpes":[],"_cs_cves":[],"_cs_exploited":false,"_cs_has_poc":false,"_cs_poc_references":[],"_cs_products":["Roundcube"],"_cs_severities":["critical"],"_cs_tags":["code-execution","roundcube","vulnerability","webmail"],"_cs_type":"advisory","_cs_vendors":["Roundcube"],"content_html":"\u003cp\u003eA vulnerability exists in Roundcube that allows a remote, authenticated attacker to execute arbitrary program code. The exact nature of the vulnerability is not specified in the source, but the impact suggests it could involve command injection, insecure deserialization, or other code execution flaws. Successful exploitation would allow the attacker to gain control of the Roundcube server, potentially compromising sensitive email data, user credentials, and other resources on the system. Defenders should apply available patches or mitigation measures to prevent exploitation of this vulnerability. This vulnerability was reported in May 2026.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eThe attacker gains valid credentials for a Roundcube user account, likely through credential stuffing, phishing, or purchasing stolen credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker authenticates to the Roundcube web interface using the compromised credentials.\u003c/li\u003e\n\u003cli\u003eThe attacker identifies a vulnerable endpoint or function within Roundcube, such as a file upload feature, plugin, or configuration setting.\u003c/li\u003e\n\u003cli\u003eThe attacker crafts a malicious request containing a payload designed to exploit the vulnerability. This payload could be a command injection string, serialized object, or other exploit code.\u003c/li\u003e\n\u003cli\u003eThe attacker sends the malicious request to the vulnerable endpoint, triggering the code execution vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker\u0026rsquo;s payload executes arbitrary code on the Roundcube server, potentially as the web server user.\u003c/li\u003e\n\u003cli\u003eThe attacker uses the initial code execution to establish a persistent foothold, such as installing a web shell or back door.\u003c/li\u003e\n\u003cli\u003eThe attacker leverages the foothold to escalate privileges, move laterally within the network, and exfiltrate sensitive data.\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of this vulnerability can lead to complete compromise of the Roundcube server. Attackers can gain access to sensitive email data, user credentials, and other confidential information stored on the server. The compromised server can also be used as a launching point for further attacks against other systems on the network. The number of affected installations is unknown, but given the widespread use of Roundcube, the potential impact is significant.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eExamine Roundcube webserver logs for suspicious POST requests containing shell metacharacters or unusual data formats (see Sigma rule \u003ccode\u003eDetect Suspicious Roundcube POST Requests\u003c/code\u003e).\u003c/li\u003e\n\u003cli\u003eImplement network segmentation to limit the impact of a successful server compromise.\u003c/li\u003e\n\u003cli\u003eMonitor Roundcube server processes for unusual activity, such as the execution of shell commands or the creation of new files in unexpected locations (see Sigma rule \u003ccode\u003eDetect Suspicious Process Execution from Web Server\u003c/code\u003e).\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-05-22T07:28:22Z","date_published":"2026-05-22T07:28:22Z","id":"https://feed.craftedsignal.io/briefs/2026-05-roundcube-rce/","summary":"A remote, authenticated attacker can exploit a vulnerability in Roundcube to execute arbitrary program code, potentially leading to complete system compromise.","title":"Roundcube Vulnerability Allows Remote Code Execution","url":"https://feed.craftedsignal.io/briefs/2026-05-roundcube-rce/"}],"language":"en","title":"CraftedSignal Threat Feed — Webmail","version":"https://jsonfeed.org/version/1.1"}