# CVE-2015-8854: marked project marked ReDoS in em inline rule

Source: https://junglewise.ai/threats/cve-2015-8854-marked-project-marked-redos-in-em-inline-rule  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2017-01-23. Updated: 2026-05-13  
License: CC BY 4.0 with a link back

CVE-2015-8854 · Severity: high · CVSS 7.5 · Published 2017-01-23

The 'marked' library, a popular Markdown parser for Node.js, is vulnerable to a denial-of-service attack. An attacker can provide specially crafted Markdown text that causes the server to consume excessive CPU resources, potentially leading to a complete service outage. This can disrupt business operations by making applications that process user-supplied Markdown unresponsive.

Technologies: [marked (npm)](https://junglewise.ai/threats/technologies/npm-marked). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2015-8854 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2015-8854 being exploited in the wild.

**How severe is CVE-2015-8854?** High severity, with a CVSS score of 7.5, published 23 January 2017.

**Which products and versions are affected?** marked (npm) SEMVER:introduced=0,fixed=0.3.4.

**Is there a fix for CVE-2015-8854?** Yes. marked (npm): upgrade to 0.3.4 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2015-8854 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2015-8854?** Check whether you run marked (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- marked (npm): upgrade to 0.3.4 or later

  ```sh
  npm install marked@0.3.4
  ```


## Technical details

A Regular Expression Denial of Service (ReDoS) vulnerability exists in the 'marked' library before version 0.3.4. The vulnerability is caused by catastrophic backtracking in the regular expression used for the 'em' (emphasis) inline rule. A remote, unauthenticated attacker can exploit this by submitting a specially crafted Markdown string that triggers inefficient processing, leading to high CPU utilization and a denial of service (DoS) condition. The issue was addressed in version 0.3.4, though some later advisories suggest further related fixes in version 0.3.9.

## Affected products

- marked_project marked < 0.3.4

## Identifiers

- CVE-2015-8854
- GHSA-hjcp-j389-59ff

## Timeline

- 2015-08-01: disclosed: Vulnerability identified in Node Security Advisory 23
- 2017-01-23: advisory: NVD published CVE-2015-8854
- 2020-05-31: patched: Fedora updates released for affected versions

## References

- [http://www.openwall.com/lists/oss-security/2016/04/20/11](http://www.openwall.com/lists/oss-security/2016/04/20/11)
- [https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BO2RMVVZVV6NFTU46B5RYRK7ZCXYARZS/](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BO2RMVVZVV6NFTU46B5RYRK7ZCXYARZS/)
- [https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M6BJG6RGDH7ZWVVAUFBFI5L32RSMQN2S/](https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M6BJG6RGDH7ZWVVAUFBFI5L32RSMQN2S/)
- [https://nodesecurity.io/advisories/23](https://nodesecurity.io/advisories/23)
- [https://support.f5.com/csp/article/K05052081?utm_source=f5support&amp%3Butm_medium=RSS](https://support.f5.com/csp/article/K05052081?utm_source=f5support&amp%3Butm_medium=RSS)

## Related threats

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- [Marked Regular Expression Denial of Service (ReDoS)](https://junglewise.ai/threats/cve-2018-25110-marked-regular-expression-denial-of-service-redos)
- [marked Regular Expression Denial of Service in inline.reflinkSearch](https://junglewise.ai/threats/cve-2022-21681-marked-regular-expression-denial-of-service-in-inline)
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