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CVE-2019-25103

CVE-2019-25103: Regular Expression Denial of Service in simple-markdown

7.5

CVSS Score
3.1

Basic Information

CVE ID
CVE-2019-25103
GHSA ID
GHSA-gpvj-gp8c-c7p2
EPSS Score
0.12588%
CWE
CWE-1333
Published
2/12/2023
Updated
10/20/2023
KEV Status
No
Technology
TechnologyJavaScript

Technical Details

CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Package NameEcosystemVulnerable VersionsFirst Patched Version
simple-markdownnpm< 0.5.20.5.2

Vulnerability Intelligence
Miggo AIMiggo AI

Miggo AIRoot Cause Analysis

The vulnerability stems from the regex pattern used for inline code parsing in simple-markdown.js. The commit diff shows the vulnerable regex had \s* before/after the content capture group ([\s\S]?[^`]), creating ambiguity in space parsing. This ambiguity led to catastrophic backtracking (CWE-1333). The patch removes these \s quantifiers and adds post-processing for spaces, confirming the regex was the root cause. The function is clearly identified in the defaultRules.inlineCode.match property in simple-markdown.js.

Vulnerable functions

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WAF Protection Rules

WAF Rule

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Reasoning

T** vuln*r**ility st*ms *rom t** r***x p*tt*rn us** *or inlin* *o** p*rsin* in simpl*-m*rk*own.js. T** *ommit *i** s*ows t** vuln*r**l* r***x *** \s* ***or*/**t*r t** *ont*nt **ptur* *roup ([\s\S]*?[^`]), *r**tin* *m*i*uity in sp*** p*rsin*. T*is *m*