Markdown Explorer 0.1.1 - Persistent Cross-Site Scripting

published 2026-01-16 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-2896

cvss: 6.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 28%
public exploits: 0; none known

Markdown Explorer 0.1.1 contains a cross-site scripting vulnerability that allows attackers to inject malicious code through file uploads and editor inputs. Attackers can upload markdown files with embedded JavaScript payloads that execute in the application's privileged renderer context, allowing code execution on the host.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 9 mo ago (2026-01-16)

Exploit prediction

0.35% chance of exploitation in the next 30 days, higher than 28% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

exploit-db.com https://www.exploit-db.com/exploits/49826 referenced PoC, tagged "exploit" by a source, unverified
imgur.com https://imgur.com/a/w4bcPWs referenced PoC, tagged "exploit" by a source, unverified
vulncheck.com https://www.vulncheck.com/advisories/markdown-explorer-persistent-cross-site-scripting referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	5.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
CNA	3.1	6.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CNA	4.0	5.1	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/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

Affected products

jersou Markdown Explorer

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

exploit-db.com /exploits/49826
exploit
imgur.com /a/w4bcPWs
exploit
vulncheck.com /advisories/markdown-explorer-persistent-cross-site-scripting
third-party-advisory, exploit
github.com /jersou/markdown-explorer
product

Sources

CVE List CVE-2021-47836
NVD CVE-2021-47836

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary