What is CVE-2021-30027?

CVE-2021-30027 is a medium-severity vulnerability in Md4c Project, classified under Use of Uninitialized Resource. CVSS score: 5.5/10. Published 2021-04-29.

How severe is CVE-2021-30027?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Vulnerability in Md4c Project

CVE-2021-30027

md_analyze_line in md4c.c in md4c 0.4.7 allows attackers to trigger use of uninitialized memory, and cause a denial of service via a malformed Markdown document.

Published 2021-04-29 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.007 (51.1th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 51.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Md4c Project — versions 0.4.7

Weakness classification (CWE)

CWE-908 — Use of Uninitialized Resource

References

github.com/mity/md4c/issues/155 (Exploit, Third Party Advisory, Issue Tracking)
github.com/mity/md4c/commit/4fc808d8fe8d8904f8525bb4231d854f45e23a19 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-30027?: CVE-2021-30027 is a medium-severity vulnerability in Md4c Project, classified under Use of Uninitialized Resource. CVSS score: 5.5/10. Published 2021-04-29.
How severe is CVE-2021-30027?: Medium severity. CVSS v3 base score is 5.5 out of 10.