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CVE-2023-42821

23
FAUCET Score

CVE-2023-42821 is an out-of-bounds read vulnerability affecting the gomarkdown/markdown Go library when parsing malformed Markdown input with the parser.Mmark extension enabled. This flaw, tracked as CWE-125, can lead to a denial of service due to a panic in citation.go. It carries a CVSS score of 7.5 (HIGH), indicating a network-exploitable vulnerability with low attack complexity and high availability impact. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:gomarkdown:markdown:-:*:*:*:*:go:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.04%
Probability of exploitation in next 30 days
EPSS Percentile
60.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0104 is in the 37th percentile among its peer group of 51,506 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (8)

github_advisorypatch availablevia nvd_reference
View patch
gopatch availablevia ghsa
Product: github.com/gomarkdown/markdownFixed in: 0.0.0-20230922105210-14b16010c2ee
microsoftpatch availablevia msrc
Product: 19777-17086Fixed in: 1.21.7-2
microsoftpatch availablevia msrc
Product: cbl2 cri-o 1.21.7-2 on CBL Mariner 2.0Fixed in: 1.21.7-2
microsoftpatch availablevia msrc
Product: cbl2 cri-o 1.22.3-14 on CBL Mariner 2.0Fixed in: 1.21.7-2
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 1.21.7-2
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 1.21.7-2
microsoftpatch availablevia msrc
Product: 17367-16823Fixed in: 1.21.7-2

Vendor Advisories (3)

microsoft2024-Apr/CVE-2023-42821

CVE-2023-42821

Apr 9, 2024
goGHSA-m9xq-6h2j-65r2high

Markdown vulnerable to Out-of-bounds Read while parsing citations

Sep 22, 2023
microsoft2023-Sep/CVE-2023-42821Important

github.com/gomarkdown/markdown Out-of-bounds Read while parsing citations

Sep 12, 2023

References

github.com / gomarkdown/markdown/blob/7478c230c7cd3e7328803d89abe591d0b61c41e4/parser/citation.go
Product
github.com / gomarkdown/markdown/commit/14b16010c2ee7ff33a940a541d993bd043a88940
Patch
github.com / gomarkdown/markdown/security/advisories/GHSA-m9xq-6h2j-65r2
ExploitVendor Advisory