CRITICAL

CVE-2018-20355

CVSS v3

9.8

CRITICAL

EPSS Score

3.6 %

exploit probability, as of 2026-10-19

CISA KEV

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2018-20355 yet.

Full record on NVD

Description

An invalid write of 8 bytes due to a use-after-free vulnerability in the mg_http_free_proto_data_cgi function call in mongoose.c in Cesanta Mongoose Embedded Web Server Library 6.13 and earlier allows a denial of service (application crash) or remote code execution.

Technical details

Published: 2019-06-10

Frequently asked questions

What is CVE-2018-20355?

Is CVE-2018-20355 actively exploited?

Active exploitation of CVE-2018-20355 has not been confirmed. Its EPSS score was 3.6% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2018-20355?

CVE-2018-20355 has a CVSS v3 base score of 9.8 (CRITICAL severity).

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