CVE-2019-9844
Cross-Site Scripting in simple-markdown
simple-markdown.js in Khan Academy simple-markdown before 0.4.4 allows XSS via a data: or vbscript: URI.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
simple-markdown.js in Khan Academy simple-markdown before 0.4.4 allows XSS via a data: or vbscript: URI.
- Record
CVE-2019-9844- CVSS 3.0
- 6.1 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
CVE List No score
simple-markdown.js in Khan Academy simple-markdown before 0.4.4 allows XSS via a data: or vbscript: URI.
- Record
CVE-2019-9844- Updated
- 2026-11-02
EUVDEUVD-2019-0428 No score
simple-markdown.js in Khan Academy simple-markdown before 0.4.4 allows XSS via a data: or vbscript: URI.
- Record
EUVD-2019-0428- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-qj3f-9gmq-fwv5
Cross-Site Scripting in simple-markdown
Versions of simple-markdown prior to 0.4.4 are vulnerable to Cross-Site Scripting. Due to insufficient input sanitization the package may render output containing malicious JavaScript. This vulnerability can be exploited through input of links containing data or VBScript URIs and a base64-encoded payload.
Recommendation
Upgrade to version 0.4.4 or later.
- Record
GHSA-qj3f-9gmq-fwv5- CVSS 3.0
- 6.1 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
simple-markdown.js in Khan Academy simple-markdown before 0.4.4 allows XSS via a data: or vbscript: URI.
- Record
CVE-2019-9844- CVSS 3.0
- 6.1 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-qj3f-9gmq-fwv5
Cross-Site Scripting in simple-markdown
Versions of simple-markdown prior to 0.4.4 are vulnerable to Cross-Site Scripting. Due to insufficient input sanitization the package may render output containing malicious JavaScript. This vulnerability can be exploited through input of links containing data or VBScript URIs and a base64-encoded payload.
Recommendation
Upgrade to version 0.4.4 or later.
- Record
GHSA-qj3f-9gmq-fwv5- CVSS 3.0
- 6.1 Medium
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
simple-markdownnpm |
before 0.4.4 | 0.4.4 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2019-9844 is a medium vulnerability (CVSS 6.1) in Khanacademy Simple-markdown, published March 15, 2019. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.27%, the 70th percentile. Fixed in simple-markdown 0.4.4.
References
github.com/Khan/simple-markdown/pull/63
npmjs.com/package/simple-markdown/v/0.4.4
lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KZG2I7VH7WLSEUQ77KYP5CRAVFT2RK2U
nvd.nist.gov/vuln/detail/CVE-2019-9844
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