CVE-2021-21254

mediumPriorität · verfolgen · 27EPSS 0.018 · 79. PerzentilEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
1.81% (79th) EPSS
CVSS 4 · medium
Is it mine?
3 products
Prüfe deine Angriffsfläche
Who says so?
4 sources
cnnvd · enisa_euvd · nvd · osv

EPSS · bewertet 2026-10-26

CKEditor 5 is an open source rich text editor framework with a modular architecture. The CKEditor 5 Markdown plugin (@ckeditor/ckeditor5-markdown-gfm) before version 25.0.0 has a regex denial of service (ReDoS) vulnerability. The vulnerability allowed to abuse link recognition regular expression, which could cause a significant performance drop resulting in browser tab freeze. It affects all users using CKEditor 5 Markdown plugin at version <= 24.0.0. The problem has been recognized and patched. The fix will be available in version 25.0.0.

01

cvss

Technischer Schweregrad, 0–10. Eine Zeile je Quelle.

6.5
010

Basiswert 0–10 · höher = schwerwiegender · Vektor überfahren zum Auflösen

v2.04mediumAV:N/AC:L/Au:S/C:N/I:N/A:Pprimary · NVD / NIST USAusnutzbarkeit 8 · Auswirkung 2.9
v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USAusnutzbarkeit 2.8 · Auswirkung 3.6
v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU
v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · security-advisories@github.comAusnutzbarkeit 2.8 · Auswirkung 3.6
v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Hsecondary · OSV
v3.16mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
02

schwächen

Die CWE-Schwächeklassen, zu denen dies gehört.

CWE-400USCWE-400US
03

betroffene Produkte (3)

Betroffene Produkte und Versionsbereiche.

04

Advisories (1)

Hersteller- und Ökosystem-Meldungen dazu.

  • GHSA-hgmg-hhc8-g5wrCKEditor 5 Markdown plugin Regular expression Denial of Service2021-01-29ghsa · osvUS

    ### Impact A regular expression denial of service (ReDoS) vulnerability has been discovered in the CKEditor 5 Markdown plugin code. The vulnerability allowed to abuse a link recognition regular expression, which could cause a significant performance drop resulting in a browser tab freeze. It affects all users using the CKEditor 5 Markdown plugin at version <= 24.0.0. ### Patches The problem has been recognized and patched. The fix will be available in version 25.0.0. ### Workarounds The user can work around the issue by: - Upgrading CKEditor 5 to version 25.0.0. - Disabling the Markdown plugin. ### More information If you have any questions or comments about this advisory: * Email us at [security@cksource.com](mailto:security@cksource.com) ### Acknowledgements The CKEditor 5 team would like to thank Erik Krogh Kristensen from the GitHub team for recognizing this vulnerability and Alvaro Muñoz from GitHub for reporting it.

05

auch bekannt als (3)

Weitere Namen und Kennungen dieser Entität.

06

quellen

Welche Quellen diesen Datensatz belegen und wann.

cnnvdenisa_euvdnvdosvNVDCVE.orgMITRE
veröffentlicht 2021-01-29geändert 2026-06-17
07

Referenzen (10)

Externe Belege — Patches, Meldungen, Analysen.

scry

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