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Fencer Vulns
high 7.2

CVE-2021-47838 json

Markright 1.0 - Persistent Cross-Site Scripting

published 2026-01-16 9 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-2901

cvss
7.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

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.

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
9 mo ago

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • exploit-db.com https://www.exploit-db.com/exploits/49834 referenced PoC, tagged "exploit" by a source, unverified
  • imgur.com https://imgur.com/a/VOsgKbZ referenced PoC, tagged "exploit" by a source, unverified
  • vulncheck.com https://www.vulncheck.com/advisories/markright-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:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
CNA 3.1 7.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
CNA 4.0 5.1 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/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

  • dvcrn Markright

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

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.