CVE-2026-30838 is a cross-site scripting (XSS) vulnerability in league/commonmark, a PHP Markdown parser, affecting versions prior to 2.8.1 when using the DisallowedRawHtml extension. An attacker can bypass the extension's sanitization by inserting whitespace between a disallowed HTML tag name and the closing bracket, allowing malicious HTML to be rendered. This medium-severity vulnerability (CVSS 5.1) has a low attack complexity and requires user interaction, potentially leading to information disclosure and integrity compromise. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.
| Vendor | Product | Version(s) | CPE |
|---|---|---|---|
< 2.8.1CPE matchmatch criteria | cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
CVSS version used by this source: 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.
No media coverage found for this CVE.
The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.