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Medium

Security advisory

Type: advisorySources: OSVCVE: CVE-2021-20727

Cross-site scripting vulnerability in Zettlr from 0.20.0 to 1.8.8 allows an attacker to execute an arbitrary script by loading a file or code snippet containing an invalid iframe into Zettlr.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2021-20727
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 11:19 UTC · Revision 1

Source evidence

CVE-2021-20727

core-osv · Original source

Published 27 May 2021, 09:15 UTC

Cross-site scripting vulnerability in Zettlr from 0.20.0 to 1.8.8 allows an attacker to execute an arbitrary script by loading a file or code snippet containing an invalid iframe into Zettlr.

osv:CVE-2021-20727
Complete source record
{
  "id": "54faa1a96021207b53800fcacf34545d62d9e618eda6627fe4b89ffb1578f319",
  "url": "https://osv.dev/vulnerability/CVE-2021-20727",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-20727",
    "summary": "Cross-site scripting vulnerability in Zettlr from 0.20.0 to 1.8.8 allows an attacker to execute an arbitrary script by loading a file or code snippet containing an invalid iframe into Zettlr.",
    "evidence": "osv:CVE-2021-20727",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-20727",
      "aliases": [
        "CVE-2021-20727"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/zettlr/zettlr",
              "type": "GIT",
              "events": [
                {
                  "introduced": "3beb5ccc97da020b1b48a256c1cfd1a146514710"
                },
                {
                  "last_affected": "4d72f9c9c7f3703c850996ad3142336c61fa4f3c"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:zettlr:zettlr:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0.20.0"
                      },
                      {
                        "last_affected": "1.8.8"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.8.8",
            "v1.8.7",
            "v1.8.6",
            "v1.8.5",
            "v1.8.4",
            "v1.8.3",
            "v1.8.2",
            "v1.8.1",
            "v1.8.0",
            "1.8.0",
            "1.8.0-beta.4",
            "1.8.0-beta.3",
            "1.8.0-beta.2",
            "1.8.0-beta.1",
            "1.8.0-beta",
            "1.8.0-alpha.3",
            "1.8.0-alpha.2",
            "1.8.0-alpha.1",
            "v1.8.0-alpha",
            "v1.7.5",
            "v1.7.4",
            "v1.7.3",
            "v1.7.2",
            "v1.7.1",
            "v1.7.0",
            "v1.7.0-beta.13",
            "v1.7.0-beta.12",
            "v1.7.0-beta.11",
            "v1.7.0-beta.10",
            "v1.7.0-beta.9",
            "v1.7.0-beta.8",
            "v1.7.0-beta.7",
            "v1.7.0-beta.6",
            "v1.7.0-beta.5",
            "v1.7.0-beta.4",
            "v1.7.0-beta.3",
            "v1.7.0-beta.2",
            "v1.7.0-beta.1",
            "v1.7.0-beta",
            "v1.6.0",
            "v1.6.0-beta.5",
            "v1.6.0-beta.4",
            "v1.6.0-beta.3",
            "v1.6.0-beta.2",
            "v1.6.0-beta.1",
            "v1.6.0-beta",
            "v1.5.0",
            "v1.5.0-beta.2",
            "v1.5.0-beta.1",
            "v1.5.0-beta",
            "v1.4.3",
            "v1.4.2",
            "v1.4.1",
            "v1.4.0",
            "v1.4.0-beta.2",
            "v1.4.0-beta.1",
            "v1.4.0-beta",
            "v1.3.0",
            "v1.3.0-beta.2",
            "v1.3.0-beta.1",
            "v1.3.0-beta",
            "v1.3.0-alpha",
            "v1.2.3",
            "v1.2.2",
            "v1.2.1",
            "v1.2.0",
            "v1.2.0-beta.1",
            "v1.2.0-beta",
            "v1.1.0",
            "v1.0.0",
            "v0.20.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-20727.json"
          }
        }
      ],
      "modified": "2026-10-20T10:53:53.385874454Z",
      "provider": "osv",
      "references": [
        "https://www.zettlr.com/",
        "https://github.com/Zettlr/Zettlr",
        "https://jvn.jp/en/jp/JVN98239374/index.html"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-20727",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 384729,
  "published_at": "2021-05-27T09:15:07.533+00:00"
}