7.5

CVE-2021-34432: eclipse mosquitto Improper Input Validation

CVSS: 7.5v3.1HighModified
AliasesALPINE-CVE-2021-34432UBUNTU-CVE-2021-34432DEBIAN-CVE-2021-34432
Published 27-07-2021Last modified 02-07-2026
Open JSON

Vulnerability summary

CVE-2021-34432 is a high (CVSS 7.5) Improper Input Validation vulnerability in eclipse mosquitto. EPSS estimates a 1.25% chance of exploitation in the next 30 days, higher than 68.8% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk
40/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
1.25%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference

Timeline

  1. 27-07-2021
    PublishedVulnerability first disclosed.
  2. 02-07-2026
    Last modifiedVulnerability information updated.

Description

In Eclipse Mosquitto versions 2.0.7 and earlier, the server will crash if the client tries to send a PUBLISH packet with topic length = 0.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

1.25%

Chance of exploitation in the next 30 days

Percentile

69%

Versus all other CVEs

30-day change

0.00 pp

From 1.25% on 18-09-2026

18-09-202618-10-2026
EPSS score
1.25%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (bugs.eclipse.org)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Alpine1 product
  • mosquitto< 1.6.8-r1 | < 1.6.9-r1 | < 1.6.12-r3 | < 2.0.8-r0
Debian1 product
  • mosquitto< 2.0.8-1
Eclipse1 product
The eclipse foundation1 product
Ubuntu1 product
  • mosquitto< 2.0.11-1ubuntu1

5 vendors · 5 products

References

6 links