CVE-2026-93563

7.5 highEPSS 0.3%

High (7.5). EPSS 0.3% chance of exploitation in the next 30 days.

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.

Severity

CVSS 3.1

7.5 high

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.3% chance of exploitation in the next 30 days; higher than 25% of CVEs (scores of 2026-10-31)
CWE: CWE-1035
Published: 2026-09-18
Modified: 2026-09-25
Record from: the NVD, synced 2026-10-19

References

https://access.redhat.com/security/cve/CVE-2026-93563
https://bugzilla.redhat.com/show_bug.cgi?id=2536976

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