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TI-2021-08459 Aliases CVE-2021-26835GHSA-m4hh-q8q7-hhmv

No filtering of cross-site scripting (XSS) payloads in the markdown-editor in Zettlr…

Priority LOW 30CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
Low · Low · None
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-79.

Summary

No filtering of cross-site scripting (XSS) payloads in the markdown-editor in Zettlr 1.8.7 allows attackers to perform remote code execution via a crafted file.

Why it matters now

EPSS 0.01291 70th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:zettlr:zettlr:1.8.7:*:*:*:*:*:*:*1.8.7VulnerableZettlr
  • cpe:2.3:a:zettlr:zettlr:1.8.7:*:*:*:*:*:*:* Versions 1.8.7 Vulnerable ·Zettlr

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-26835
  2. 2026-10-03 Alias added: GHSA-m4hh-q8q7-hhmv

References

Exploit 1

Advisory 1

  • TI-2021-03953 Cross-site scripting in Hendrik Erz Zettlr CVSS 3.1MEDIUM 6.1
  • TI-2022-19117 Improper input validation in Zettlr CVSS 3.1MEDIUM 5.5

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences