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MEDIUM severity

CVE-2021-26272 — ckeditor4

MEDIUM

CVE-2021-26272 is a medium-severity (CVSS 6.5) CWE-829 vulnerability in ckeditor4. A fix is available for ckeditor4 — see the affected versions and patch details below.

Inclusion of Functionality from Untrusted Control Sphere in CKEditor 4

Also known asGHSA-wpvm-wqr4-p7cw
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
2.3%probability of exploitation in next 30 days
Lower Risk+0.08%
Lower risk than most CVEs83th percentile — riskier than 83% of all scored CVEsHighest risk
0.00%0.95%1.90%2.84%0.5%2.3%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-26272 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

27other npm packages depend on this — each one inherits the vulnerability until it's patched upstream
ckeditor4npm
56Kdownloads / week

Description

It was possible to execute a ReDoS-type attack inside CKEditor 4 before 4.16 by persuading a victim to paste crafted URL-like text into the editor, and then press Enter or Space (in the Autolink plugin).

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmckeditor4all versions4.16.0npm install ckeditor4@4.16.0

Affected Products

10 products · 16 configurations
Application
ckeditorckeditor
≥ 4.0 && < 4.16
range
Application
agile product lifecycle managementoracle
2 versions
9.3.59.3.6
Application
application expressoracle
< 21.1.0
range
Application
banking party managementoracle
1 version
2.7.0
Application
commerce merchandisingoracle
≥ 11.3.0 && ≤ 11.3.2
2 versions
11.1.011.2.0
Application
financial services analytical applications infrastructureoracle
≥ 8.0.6 && ≤ 8.0.9
2 versions
8.1.08.1.1

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ckeditor4, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update ckeditor4 to 4.16.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-26272 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

It was possible to execute a ReDoS-type attack inside CKEditor 4 before 4.16 by persuading a victim to paste crafted URL-like text into the editor, and then press Enter or Space (in the Autolink plugin).
O3 Security · Impact-Aware SCA

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CVE-2021-26272: ckeditor4 — Fixed in 4.16.0