CVE-2021-47838
Markright 1.0 - Persistent Cross-Site Scripting
Description
Markright 1.0 contains a persistent cross-site scripting vulnerability that allows attackers to embed malicious payloads in markdown files. Attackers can upload specially crafted markdown files that execute arbitrary JavaScript when opened, potentially enabling remote code execution on the victim's system.
INFO
Published Date :
Jan. 16, 2026, 7:16 p.m.
Last Modified :
Jan. 16, 2026, 7:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2021-47838
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Implement a robust markdown sanitization library.
- Encode or escape script tags and malicious HTML.
- Validate and restrict potentially dangerous characters.
- Regularly update markdown processing components.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-47838.
| URL | Resource |
|---|---|
| https://github.com/dvcrn/markright | |
| https://imgur.com/a/VOsgKbZ | |
| https://www.exploit-db.com/exploits/49834 | |
| https://www.vulncheck.com/advisories/markright-persistent-cross-site-scripting |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-47838 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-47838
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-47838 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-47838 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Jan. 16, 2026
Action Type Old Value New Value Added Description Markright 1.0 contains a persistent cross-site scripting vulnerability that allows attackers to embed malicious payloads in markdown files. Attackers can upload specially crafted markdown files that execute arbitrary JavaScript when opened, potentially enabling remote code execution on the victim's system. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/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 Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N Added CWE CWE-79 Added Reference https://github.com/dvcrn/markright Added Reference https://imgur.com/a/VOsgKbZ Added Reference https://www.exploit-db.com/exploits/49834 Added Reference https://www.vulncheck.com/advisories/markright-persistent-cross-site-scripting