5.5

CVE-2021-45936: wolfssl wolfmqtt Out-of-bounds Write

Modified
Published 31-12-2021Last modified 04-08-2024

Vulnerability summary

CVE-2021-45936 is a medium (CVSS 5.5) Out-of-bounds Write vulnerability in wolfssl wolfmqtt. EPSS estimates a 0.92% chance of exploitation in the next 30 days, higher than 60.2% of scored vulnerabilities. 2 public exploits are recorded.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.92%
0%100%
Low · +0.03 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits2github, reference

Timeline

  1. 31-12-2021
    PublishedVulnerability first disclosed.
  2. 04-08-2024
    Last modifiedVulnerability information updated.

Description

wolfSSL wolfMQTT 1.9 has a heap-based buffer overflow in MqttDecode_Disconnect (called from MqttClient_DecodePacket and MqttClient_WaitType).

CVSS metrics

2 scores · 1 source · 2 versions

EPSS trend

Probability

0.92%

Chance of exploitation in the next 30 days

Percentile

60%

Versus all other CVEs

30-day change

Increase +0.03 pp

From 0.89% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

2 found
  • githubUnverified

    Oss Fuzz Vulns

    Maturity: poc

  • referenceUnverified

    Exploit Reference (bugs.chromium.org)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: local access, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.

Wolfssl1 product

1 vendor · 1 product

References

3 links