CVE-2026-71478: league/commonmark: AttributesExtension href/src unsafe-link filter bypass via embedded control bytes
thephpleague · commonmark
Affected: thephpleague commonmark · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 29% of scored CVEs
DescriptionCVE.org
league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a javascript: URL that browsers discard before parsing the scheme, causing the browser to still execute the script even when the unsafe-link filter is enabled. This issue is fixed in 2.9.0.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- thephpleague · commonmark>= 1.5.0, <= 2.8.3
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Weakness
- Improper Neutralization of Invalid Characters in Identifiers in Web Pages · Cross-site Scripting
- Vendor
- thephpleague
- Published
- August 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-71478 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.