CVE-2021-26271
MEDIUMEPSS 78th pctlDescription
It was possible to execute a ReDoS-type attack inside CKEditor 4 before 4.16 by persuading a victim to paste crafted text into the Styles input of specific dialogs (in the Advanced Tab for Dialogs plugin).
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Exploit Intelligence
Elevated risk: more likely to be exploited than 78% of all known CVEs.
References
Related Vulnerabilities
Other CWE-829 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2018-17246 | Critical | 9.8 | 82% | - | Fix |
| CVE-2024-5762 | High | 8.1 | 72% | - | - |
| CVE-2018-7422 | High | 7.5 | 62% | - | - |
| CVE-2023-2249 | High | 8.8 | 61% | - | - |
| CVE-2025-32463 | Critical | 9.3 | 56% | KEV | Fix |
| CVE-2026-0770 | Critical | 9.8 | 56% | KEV | - |
Common questions
How do I fix CVE-2021-26271?
Upgrade ckeditor on debian 11 to 4.16.0+dfsg-1 or later.
Is CVE-2021-26271 being actively exploited?
Not that we know of. CVE-2021-26271 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 2.0% is the estimated probability that it will be exploited in the next 30 days. That is higher than 78% of all scored CVEs.
How severe is CVE-2021-26271?
CVE-2021-26271 has a CVSS v3 base score of 6.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-26271 affect?
Published advisories record a fix for ckeditor (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2021-26271
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.