{"description":"Trending threats, MITRE ATT\u0026CK coverage, and detection metadata — refreshed continuously.","feed_url":"https://feed.craftedsignal.io/products/exim--4.99.2/","home_page_url":"https://feed.craftedsignal.io/","items":[{"_cs_actors":[],"_cs_cves":[],"_cs_exploited":false,"_cs_products":["Exim (\u003c 4.99.2)"],"_cs_severities":["high"],"_cs_tags":["vulnerability","denial-of-service","information-disclosure"],"_cs_type":"advisory","_cs_vendors":["Exim"],"content_html":"\u003cp\u003eOn April 30, 2026, CERT-FR published an advisory regarding multiple vulnerabilities affecting Exim versions prior to 4.99.2. These vulnerabilities could allow a remote attacker to perform a denial-of-service attack, achieve unauthorized data access, or cause other unspecified security impacts. The vulnerabilities are detailed in the Exim security bulletin cve-2026-04.1. Due to the widespread use of Exim as a mail transfer agent (MTA), these vulnerabilities pose a significant risk to organizations that have not yet applied the necessary patches. Successful exploitation can disrupt email services and potentially lead to sensitive information disclosure.\u003c/p\u003e\n\u003ch2 id=\"attack-chain\"\u003eAttack Chain\u003c/h2\u003e\n\u003col\u003e\n\u003cli\u003eAttacker identifies an Exim server running a vulnerable version (prior to 4.99.2).\u003c/li\u003e\n\u003cli\u003eThe attacker crafts a malicious network packet targeting a specific vulnerability, such as CVE-2026-40684, CVE-2026-40685, CVE-2026-40686, or CVE-2026-40687.\u003c/li\u003e\n\u003cli\u003eThe attacker sends the crafted packet to the vulnerable Exim server via SMTP.\u003c/li\u003e\n\u003cli\u003eThe Exim process receives the malicious packet and processes it due to missing or insufficient input validation.\u003c/li\u003e\n\u003cli\u003eDepending on the exploited vulnerability, this could lead to a denial-of-service condition by crashing the Exim process.\u003c/li\u003e\n\u003cli\u003eAlternatively, successful exploitation may lead to an information leak by disclosing sensitive data from Exim\u0026rsquo;s memory.\u003c/li\u003e\n\u003cli\u003eIn other cases, the unspecified security issue could grant further access to the underlying system, depending on the nature of vulnerability.\u003c/li\u003e\n\u003cli\u003eThe attacker exploits this access to achieve goals like data exfiltration or further system compromise (depending on the specific vulnerability triggered).\u003c/li\u003e\n\u003c/ol\u003e\n\u003ch2 id=\"impact\"\u003eImpact\u003c/h2\u003e\n\u003cp\u003eSuccessful exploitation of these vulnerabilities could lead to denial-of-service conditions, preventing legitimate users from sending and receiving emails. Data confidentiality could also be compromised if sensitive information is exposed. The advisory does not specify the number of victims or specific sectors targeted, but given the widespread use of Exim, a large number of organizations could be affected. Failure to patch Exim servers could result in significant disruption of email services and potential data breaches.\u003c/p\u003e\n\u003ch2 id=\"recommendation\"\u003eRecommendation\u003c/h2\u003e\n\u003cul\u003e\n\u003cli\u003eImmediately upgrade Exim servers to version 4.99.2 or later to remediate the vulnerabilities mentioned in the Exim security bulletin cve-2026-04.1.\u003c/li\u003e\n\u003cli\u003eMonitor network traffic for suspicious activity targeting Exim servers, and correlate with the known CVEs (CVE-2026-40684, CVE-2026-40685, CVE-2026-40686, CVE-2026-40687).\u003c/li\u003e\n\u003cli\u003eImplement rate limiting and connection filtering to mitigate potential denial-of-service attacks against Exim servers.\u003c/li\u003e\n\u003cli\u003eDeploy a web server rule that monitors for requests matching known attack patterns related to Exim vulnerabilities.\u003c/li\u003e\n\u003c/ul\u003e\n","date_modified":"2026-04-30T00:00:00Z","date_published":"2026-04-30T00:00:00Z","id":"/briefs/2026-04-exim-vulns/","summary":"Multiple vulnerabilities in Exim versions prior to 4.99.2 allow an attacker to cause a remote denial of service, a breach of data confidentiality, and an unspecified security problem.","title":"Multiple Vulnerabilities in Exim Mail Transfer Agent","url":"https://feed.craftedsignal.io/briefs/2026-04-exim-vulns/"}],"language":"en","title":"CraftedSignal Threat Feed — Exim (\u003c 4.99.2)","version":"https://jsonfeed.org/version/1.1"}