Marked Project: Security Vulnerabilities
Marked is a markdown parser and compiler. From 18.0.0 to 18.0.1, a critical Denial of Service (DoS) vulnerability exists in marked. By providing a specific 3-byte input sequence a tab, a vertical tab, and a newline (\x09\x0b\n)—an unauthenticated attacker can trigger an infinite recursion loop during parsing. This leads to unbounded memory allocation, causing the host Node.js application to crash via Memory Exhaustion (OOM). This vulnerability is fixed in 18.0.2.
CVSS Score
8.7
EPSS Score
0.001
Published
2026-04-24
Marked prior to version 0.3.17 is vulnerable to a Regular Expression Denial of Service (ReDoS) attack due to catastrophic backtracking in several regular expressions used for parsing HTML tags and markdown links. An attacker can exploit this vulnerability by providing specially crafted markdown input, such as deeply nested or repetitively structured brackets or tag attributes, which cause the parser to hang and lead to a Denial of Service.
CVSS Score
6.9
EPSS Score
0.008
Published
2025-05-23
Marked is a markdown parser and compiler. Prior to version 4.0.10, the regular expression `block.def` may cause catastrophic backtracking against some strings and lead to a regular expression denial of service (ReDoS). Anyone who runs untrusted markdown through a vulnerable version of marked and does not use a worker with a time limit may be affected. This issue is patched in version 4.0.10. As a workaround, avoid running untrusted markdown through marked or run marked on a worker thread and set a reasonable time limit to prevent draining resources.
CVSS Score
7.5
EPSS Score
0.007
Published
2022-01-14
Marked is a markdown parser and compiler. Prior to version 4.0.10, the regular expression `inline.reflinkSearch` may cause catastrophic backtracking against some strings and lead to a denial of service (DoS). Anyone who runs untrusted markdown through a vulnerable version of marked and does not use a worker with a time limit may be affected. This issue is patched in version 4.0.10. As a workaround, avoid running untrusted markdown through marked or run marked on a worker thread and set a reasonable time limit to prevent draining resources.
CVSS Score
7.5
EPSS Score
0.005
Published
2022-01-14
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 Score
5.3
EPSS Score
0.006
Published
2021-02-08
Multiple cross-site scripting (XSS) vulnerabilities in the Marked module before 0.3.1 for Node.js allow remote attackers to inject arbitrary web script or HTML via vectors related to (1) gfm codeblocks (language) or (2) javascript url's.
CVSS Score
6.1
EPSS Score
0.004
Published
2020-01-06
The marked module is vulnerable to a regular expression denial of service. Based on the information published in the public issue, 1k characters can block for around 6 seconds.
CVSS Score
7.5
EPSS Score
0.004
Published
2018-06-07
marked is an application that is meant to parse and compile markdown. Due to the way that marked 0.3.5 and earlier parses input, specifically HTML entities, it's possible to bypass marked's content injection protection (`sanitize: true`) to inject a `javascript:` URL. This flaw exists because `&#xNNanything;` gets parsed to what it could and leaves the rest behind, resulting in just `anything;` being left.
CVSS Score
6.1
EPSS Score
0.003
Published
2018-05-31
marked version 0.3.6 and earlier is vulnerable to an XSS attack in the data: URI parser.
CVSS Score
6.1
EPSS Score
0.004
Published
2018-01-02
The marked package before 0.3.4 for Node.js allows attackers to cause a denial of service (CPU consumption) via unspecified vectors that trigger a "catastrophic backtracking issue for the em inline rule," aka a "regular expression denial of service (ReDoS)."
CVSS Score
7.5
EPSS Score
0.009
Published
2017-01-23
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