CVE-2026-30838

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Source
https://cve.org/CVERecord?id=CVE-2026-30838
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-30838.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-30838
Aliases
Downstream
Published
2026-03-07T16:00:32.351Z
Modified
2026-04-10T04:18:16.454141Z
Severity
  • 5.1 (Medium) CVSS_V4 - 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 CVSS Calculator
Summary
league/commonmark: DisallowedRawHtml extension bypass via whitespace in HTML tag names
Details

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.

Database specific 
{
    "cwe_ids": [
        "CWE-79"
    ],
    "cna_assigner": "GitHub_M",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/30xxx/CVE-2026-30838.json"
}
References

Affected packages

Git / github.com/thephpleague/commonmark

Affected ranges

Type
GIT
Repo
https://github.com/thephpleague/commonmark
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
84b1ca48347efdbe775426f108622a42735a6579
Database specific 
{
    "source": "AFFECTED_FIELD",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "2.8.1"
        }
    ]
}

Affected versions

0.*
0.1.0
0.1.1
0.1.2
0.10.0
0.11.0
0.11.1
0.11.2
0.11.3
0.12.0
0.13.0
0.13.1
0.13.2
0.13.3
0.13.4
0.14.0
0.15.0
0.15.1
0.15.2
0.15.3
0.15.4
0.15.5
0.15.6
0.15.7
0.16.0
0.17.0
0.17.2
0.17.4
0.18.1
0.2.0
0.2.1
0.3.0
0.4.0
0.5.0
0.5.1
0.6.0
0.6.1
0.7.0
0.7.1
0.8.0
0.9.0
2.*
2.0.0
2.0.0-beta1
2.0.0-beta2
2.0.0-beta3
2.0.0-rc1
2.0.0-rc2
2.0.1
2.0.2
2.1.0
2.2.0
2.3.0
2.4.0
2.5.0
2.6.0
2.7.0
2.8.0

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-30838.json"