CVE-2021-21306

mediumpriority · track · 31EPSS 0.025 · 84 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

2.46% (84th) EPSS

CVSS 5 · medium

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · nvd · osv

EPSS · scored 2026-10-27

Marked is an open-source markdown parser and compiler (npm package "marked"). In marked from version 1.1.1 and before version 2.0.0, there is a Regular expression Denial of Service vulnerability. This vulnerability can affect anyone who runs user generated code through marked. This vulnerability is fixed in version 2.0.0.

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Lsecondary · ENISA EU

v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Lsecondary · security-advisories@github.comexploitability 3.9 · impact 1.4

v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Lsecondary · OSV

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-400USprimaryCWE-400US

affected products (3)

Products and version ranges known to be affected.

markedjs marked1.1.1, → 2.0.0enisa_euvdEU
marked project marked1.1.1 → 2.0.0nvdUScpe:2.3:a:marked_project:marked:*:*:*:*:*:*:*:*
npm marked1.1.1 → 2.0.0osvUSpkg:npm/marked

advisories (1)

Vendor and ecosystem advisories describing this.

GHSA-4r62-v4vq-hr96Regular Expression Denial of Service (REDoS) in Marked2021-02-08ghsa · osvUS
### Impact _What kind of vulnerability is it? Who is impacted?_ [Regular expression Denial of Service](https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS) A Denial of Service attack can affect anyone who runs user generated code through `marked`. ### Patches _Has the problem been patched? What versions should users upgrade to?_ patched in v2.0.0 ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ None. ### References _Are there any links users can visit to find out more?_ https://github.com/markedjs/marked/issues/1927 https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS ### For more information If you have any questions or comments about this advisory: * Open an issue in [marked](https://github.com/markedjs/marked/issues)

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd osv NVD CVE.org MITRE

published 2021-02-08modified 2026-06-17

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references (17)

External citations — patches, advisories, analysis.

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