CVE detail
CVE-2026-30838
league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing >. For example, <script\n> would pass through unfiltered and be rendered as a valid HTML tag by browsers. This is a cross-site scripting (XSS) vector for any application that relies on this extension to sanitize untrusted user input. All applications using the DisallowedRawHtml extension to process untrusted markdown are affected. Applications that use a dedicated HTML sanitizer (such as HTML Purifier) on the rendered output are not affected. This issue has been patched in version 2.8.1.
Buzz score
Why this CVE is surfacing
This all-time snapshot uses the same composite formula as Trending across a 30-year evidence window, rather than a current rolling window.
Buzz score components · mention 6.9 · diversity 5.0 · KEV 0.0 · OTX 0.0 · PoC 0.0
Why it matters now
Mention timeline
- Total mentions
- 0
- within the 30d window
- Peak daily
- 0
- highest bucket
Evidence
Source links by recency
1 source links · newest first
No excerpt available.
Exploitgithub.comMar 7, 2026, 4:15 PM
Exploit code
Public exploit repository references
Public PoC repositories are third-party, potentially unsafe artifacts. Treat their code as untrusted and use it only on authorized systems in an isolated, least-privilege environment. cvebuzz does not execute the code or verify that an exploit works.
0 repository references · best confidence N/A · max 0 stars
Related records
Similar CVEs
6 related CVEs with shared weakness or product evidence
- CVE-2026-33347CVSS 6.3 · Medium
league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due…
- CVE-2019-10010CVSS 6.1 · Medium
Cross-site scripting (XSS) vulnerability in the PHP League CommonMark library before 0.18.3 allows remote attackers to insert unsafe links into HTML by using double-encoded HTML e…
- CVE-2018-20583CVSS 6.1 · Medium
Cross-site scripting (XSS) vulnerability in the PHP League CommonMark library versions 0.15.6 through 0.18.x before 0.18.1 allows remote attackers to insert unsafe URLs into HTML…
- CVE-2026-3093CVSS 4.7 · Medium
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 14.0 before 19.0.5, 19.1 before 19.1.3, and 19.2 before 19.2.1 that under certain conditions could have…
- CVE-2026-66490CVSS 6.1 · Medium
Joomla Extension - balbooa.com - Stored cross-site scripting via a comment avatar in Gridbox < 2.20.2
- CVE-2026-65946CVSS 6.1 · Medium
Joomla Extension - rolandd.com - XSS vectors in AJAX endpoint handlers RO CSVI < 9.11.0