7.5

CVE-2026-93563: netty

CVSS: 7.5v3.1HighAwaiting analysis
AliasesUBUNTU-CVE-2026-93563DEBIAN-CVE-2026-93563
Published 18-09-2026Last modified 25-09-2026
Open JSON

Vulnerability summary

CVE-2026-93563 is a high (CVSS 7.5) vulnerability in netty. EPSS estimates a 0.33% chance of exploitation in the next 30 days, higher than 24.1% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.33%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 2
OPENSUSE-SU-2026:11882-1SUSE-SU-2026:4391-1

Timeline

  1. 18-09-2026
    PublishedVulnerability first disclosed.
  2. 25-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.33%

Chance of exploitation in the next 30 days

Percentile

24%

Versus all other CVEs

30-day change

0.00 pp

From 0.33% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.33%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • nettyAll versions (No fix recorded)
Ubuntu1 product
  • nettyAll versions (No fix recorded)

2 vendors · 2 products

References

6 links