TI-2021-10627 Aliases CVE-2021-30027 GHSA-9whf-9v4j-38v8

md_analyze_line in md4c.c in md4c 0.4.7 allows attackers to trigger use of uninitialized…

LOW 26CWE-908Published 2021-04-29 · Updated 2024-08-03

Key facts

Attack vector: Local
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-908 and the CVSS impact.

Summary

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.

Why it matters now

EPSS 0.00697 53rd percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
—	—	all versions	—	No fix listed	CNA

— Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:md4c_project:md4c:0.4.7:::::::*	0.4.7	Vulnerable	Md4c Project

cpe:2.3:a:md4c_project:md4c:0.4.7:*:*:*:*:*:*:* Versions 0.4.7 Vulnerable ·Md4c Project

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2021-30027
2026-10-03 Alias added: GHSA-9whf-9v4j-38v8

References

Exploit 1

https://github.com/mity/md4c/issues/155

Patch 1

https://github.com/mity/md4c/commit/4fc808d8fe8d8904f8525bb4231d854f45e23a19

TI-2018-08257 md_is_link_reference_definition_helper in md4c 0.2.5 has a heap-based buffer over-read… CVSS 3.0CRITICAL 9.8
TI-2018-08256 md4c 0.2.5 has a heap-based buffer over-read because md_is_named_entity_contents has an off-by-one error. CVSS 3.0CRITICAL 9.8
TI-2018-08255 md4c 0.2.5 has a heap-based buffer overflow in md_merge_lines because md_is_link_label… CVSS 3.0CRITICAL 9.8
TI-2018-08248 md4c before 0.2.5 has a heap-based buffer overflow because md_split_simple_pairing_mark mishandles splits. CVSS 3.0CRITICAL 9.8
TI-2018-08688 md_build_attribute in md4c.c in md4c 0.2.6 allows remote attackers to cause a denial of… CVSS 3.0HIGH 7.8
TI-2020-15985 md_push_block_bytes in md4c.c in md4c 0.4.5 allows attackers to trigger use of… CVSS 3.1HIGH 7.5

See all 7 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences