Cross-site Scripting in Parsedown

published 2018-04-18 8 y ago modified 2026-06-17 4 mo ago also GHSA-qgpv-86r3-87fh , EUVD-2022-1520

cvss: 6.1; version 3.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.2%; EPSS 1.2% chance of exploitation in 30 days, percentile 67%
public exploits: 0; none known

Parsedown version prior to 1.7.0 contains a Cross Site Scripting (XSS) vulnerability in `setMarkupEscaped` for escaping HTML that can result in JavaScript code execution. This attack appears to be exploitable via specially crafted markdown that allows it to side step HTML escaping by breaking AST boundaries. This vulnerability appears to have been fixed in 1.7.0 and later.

Patch / fix

fixed in 2 links 1

packagist erusev/parsedown 1.7.0
parsedown parsedown 1.7.0

github.com/erusev/parsedown#495 pull request

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-1000162 updated 2026-01-13 cvss 6.1

php-erusev-parsedown: Cross Site Scripting in `setMarkupEscaped`

Red Hat All currently supported Red Hat products
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.16% chance of exploitation in the next 30 days, higher than 67% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.0	6.1	CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD	2.0	4.3	AV:N/AC:M/Au:N/C:N/I:P/A:N
GitHub	3.0	6.1	CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
packagist	erusev/parsedown	<1.7.0	1.7.0

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

github.com /erusev/parsedown/pull/495
web, third-party-advisory
github.com /Roave/SecurityAdvisories/issues/44#issuecomment-368594409
web, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2018-1000162
advisory
github.com /FriendsOfPHP/security-advisories/blob/master/erusev/parsedown/CVE-2018-1000162.yaml
web
github.com /erusev/parsedown
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary