CVE-2026-93563
Io.netty/netty-codec-smtp: netty: unbounded multi-line response accumulation in smtpresponsedecoder leads to memory-exhaustion dos
- State
- Published
- Severity
- 7.5 High
- Published
- Sep 18, 2026
- Updated
- Sep 25, 2026
- Reserved
- Sep 18, 2026
Description
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 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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | redhat |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
Red Hat build of Apache Camel for Spring Boot 4Red Hat | |
Red Hat Fuse 7Red Hat | |
Red Hat JBoss Enterprise Application Platform 7Red Hat | |
Red Hat JBoss Enterprise Application Platform 7Red Hat | |
Red Hat JBoss Enterprise Application Platform 7Red Hat | |
Red Hat JBoss Enterprise Application Platform 7Red Hat | |
Red Hat Single Sign-On 7Red Hat |
References
- https://access.redhat.com/security/cve/CVE-2026-93563vdb-entry
- RHBZ#2536976issue-tracking
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