What’s Vulnerable › Vulnerabilities

CVE-2018-25110: Regular Expression Denial of Service (ReDoS) in markedjs/marked

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2025-05-23 · updated 2026-06-17
• Weakness: CWE-1333

Description

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.

Affected products

• markedjs marked: before 0.3.17 — fixed in 0.3.17
• Npm Marked: before 0.3.17 — fixed in 0.3.17

How to fix

Upgrade to a fixed version: markedjs marked 0.3.17; Npm Marked 0.3.17. Check the vendor advisory for mitigations.

References

• https://github.com/Checkmarx/Vulnerabilities-Proofs-of-Concept/tree/main/2018/CVE-2018-25110
• https://github.com/markedjs/marked/commit/20bfc106013ed45713a21672ad4a34df94dcd485
• https://github.com/markedjs/marked/issues/1070
• https://github.com/markedjs/marked/pull/1083

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