XSS in Parsedown

CVE-2019-10905

Parsedown before 1.7.2, when safe mode is used and HTML markup is disabled, might allow attackers to execute arbitrary JavaScript code if a script (already running on the affected page) executes the contents of any element with a specific class. This occurs because spaces are permitted in code block infostrings, which interferes with the intended behavior of a single class name beginning with the language- substring.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.015 (71.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

  • cve@mitre.org (Exploit, Third Party Advisory, x_refsource_MISC, Issue Tracking)
  • cve@mitre.org (Third Party Advisory, x_refsource_MISC, Release Notes)

Frequently asked questions

What is CVE-2019-10905?
CVE-2019-10905 is a high-severity vulnerability in Parsedown, classified under Cross-site Scripting. CVSS score: 8.1/10. Published 2019-04-06.
How severe is CVE-2019-10905?
High severity. CVSS v3 base score is 8.1 out of 10.
Is CVE-2019-10905 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.