{"id":"CVE-2026-93563","title":"A flaw was found in Netty's `SmtpResponseDecoder` component","summary":"A flaw was found in Netty's `SmtpResponseDecoder` component. A remote attacker, acting as a malicious or man-in-the-middle (MITM) SMTP server, could exploit this by sending a specially crafted, unbounded multi-line SMTP response without …","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-1035"],"vendor":"Red Hat","product":"netty-codec-smtp","affected":["netty-codec-smtp (all versions)","netty-codec-smtp (all versions)","jboss-eap-7/eap74-els-openjdk11-openshift-rhel8 (all versions)","jboss-eap-7/eap74-els-openjdk17-openshift-rhel8 (all versions)","jboss-eap-7/eap74-els-openjdk8-openshift-rhel8 (all versions)","netty-codec-smtp (all versions)","netty-codec-smtp (all versions)"],"published":"2026-09-18","updated":"2026-09-18","sourceUpdated":"2026-09-18T21:18:47.130","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-93563","references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-93563","label":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2536976","label":"secalert@redhat.com"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93563.json"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-93563"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93563"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-09-18T19:07:42.549423Z"},"ingestedAt":"2026-09-18T11:40:03.681Z","epss":0.00325,"epssPercentile":0.25712,"slug":"CVE-2026-93563","body":"## Overview\n\nA flaw was found in Netty's `SmtpResponseDecoder` component. A remote attacker, acting as a malicious or man-in-the-middle (MITM) SMTP server, could exploit this by sending a specially crafted, unbounded multi-line SMTP response without a terminator. This vulnerability leads to unbounded memory accumulation within the client's Java Virtual Machine (JVM) heap, causing an `OutOfMemoryError` and a denial of service (DoS) due to a process crash.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat build of Apache Camel for Spring Boot 4, Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7 · no fix planned: Red Hat build of Apache Camel for Spring Boot 4, Red Hat Fuse 7, Red Hat JBoss Enterprise Application Platform 7, Red Hat Single Sign-On 7 · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-93563.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":206832,"id":"CVE-2026-93563","ts":1789738971933,"field":"cvss","old":null,"new":"7.5"},{"seq":206831,"id":"CVE-2026-93563","ts":1789738971933,"field":"severity","old":"none","new":"high"}]}