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CVE-2021-21306

23
FAUCET Score

CVE-2021-21306 describes a Regular Expression Denial of Service (ReDoS) vulnerability affecting the 'marked' npm package, an open-source markdown parser and compiler, in versions 1.1.1 through 1.2.9. This vulnerability allows an unauthenticated attacker to cause a denial of service by providing specially crafted user-generated input, leading to high availability impact. While the CVSS score is 7.5 (High), there is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 1.1.1, < 2.0.0CPE matchmatch criteria
cpe:2.3:a:marked_project:marked:*:*:*:*:*:node.js:*:*

CVSS Data

CVSS version used by this source: 3.1

5.3MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
LOW
Exploitability Score
3.9
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.46%
Probability of exploitation in next 30 days
EPSS Percentile
82.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0246 is in the 69th 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 (2)

github_advisorypatch availablevia nvd_reference
View patch
npmpatch availablevia ghsa
Product: markedFixed in: 2.0.0

Vendor Advisories (2)

npmGHSA-4r62-v4vq-hr96medium

Regular Expression Denial of Service (REDoS) in Marked

Feb 8, 2021
redhatCVE-2021-21306Moderate

nodejs-marked: Regular expression denial of service

Feb 8, 2021

References

github.com / markedjs/marked/commit/7293251c438e3ee968970f7609f1a27f9007bccd
PatchThird Party Advisory
github.com / markedjs/marked/issues/1927
Third Party Advisory
github.com / markedjs/marked/pull/1864
PatchThird Party Advisory
github.com / markedjs/marked/security/advisories/GHSA-4r62-v4vq-hr96
Third Party Advisory
npmjs.com / package/marked
ProductThird Party Advisory