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Inefficient Regular Expression Complexity in marked

High severity GitHub Reviewed Published Jan 14, 2022 in markedjs/marked • Updated Nov 29, 2023

Package

npm marked (npm)

Affected versions

< 4.0.10

Patched versions

4.0.10

Description

Impact

What kind of vulnerability is it?

Denial of service.

The regular expression inline.reflinkSearch may cause catastrophic backtracking against some strings.
PoC is the following.

import * as marked from 'marked';

console.log(marked.parse(`[x]: x

\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](`));

Who is impacted?

Anyone who runs untrusted markdown through marked and does not use a worker with a time limit.

Patches

Has the problem been patched?

Yes

What versions should users upgrade to?

4.0.10

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?

Do not run untrusted markdown through marked or run marked on a worker thread and set a reasonable time limit to prevent draining resources.

References

Are there any links users can visit to find out more?

For more information

If you have any questions or comments about this advisory:

References

@UziTech UziTech published to markedjs/marked Jan 14, 2022
Published by the National Vulnerability Database Jan 14, 2022
Reviewed Jan 14, 2022
Published to the GitHub Advisory Database Jan 14, 2022
Last updated Nov 29, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.225%
(62nd percentile)

Weaknesses

CVE ID

CVE-2022-21681

GHSA ID

GHSA-5v2h-r2cx-5xgj

Source code

Credits

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