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CVE-2021-26272

Inclusion of Functionality from Untrusted Control Sphere in CKEditor 4

6.5 MediumFix available

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).

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

2.35%Up 1.7 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 6.5

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).

Record
CVE-2021-26272
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS 2.0
4.3 MediumAV:N/AC:M/Au:N/C:N/I:N/A:P
Weakness
CWE-829
Updated
2026-11-02
CVE List No score

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).

Record
CVE-2021-26272
Updated
2026-11-02
EUVDEUVD-2021-2267 No score

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).

Record
EUVD-2021-2267
Updated
2026-11-03
GitHub AdvisoriesGHSA-wpvm-wqr4-p7cw 6.5

Inclusion of Functionality from Untrusted Control Sphere in CKEditor 4

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).

Record
GHSA-wpvm-wqr4-p7cw
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness
CWE-829
Updated
2026-11-02
OSV 6.5

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).

Record
CVE-2021-26272
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2021-26272 6.5

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).

Record
DEBIAN-CVE-2021-26272
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVGHSA-wpvm-wqr4-p7cw 6.5

Inclusion of Functionality from Untrusted Control Sphere in CKEditor 4

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).

Record
GHSA-wpvm-wqr4-p7cw
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness
CWE-829
Updated
2026-11-02
OSVUBUNTU-CVE-2021-26272 6.5

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).

Record
UBUNTU-CVE-2021-26272
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
ckeditor4
npm
before 4.16.0
4.16.0
ckeditor
Debian:12
before 4.16.0+dfsg-1
4.16.0+dfsg-1
ckeditor
Ubuntu:Pro:16.04:LTS
All versions, plus listed versions
4.4.4+dfsg1-34.5.6+dfsg-14.5.7+dfsg-14.5.7+dfsg-24.5.7+dfsg-2ubuntu0.16.04.1~esm14.5.7+dfsg-2ubuntu0.16.04.1~esm24.5.7+dfsg-2ubuntu0.16.04.1~esm3
None known
ckeditor
Ubuntu:Pro:18.04:LTS
All versions, plus listed versions
4.5.7+dfsg-24.5.7+dfsg-2ubuntu0.18.04.14.5.7+dfsg-2ubuntu0.18.04.1+esm14.5.7+dfsg-2ubuntu0.18.04.1+esm2
None known
ckeditor
Ubuntu:Pro:20.04:LTS
All versions, plus listed versions
4.11.1+dfsg-14.12.1+dfsg-14.12.1+dfsg-1ubuntu0.14.12.1+dfsg-1ubuntu0.1+esm14.12.1+dfsg-1ubuntu0.1+esm2
None known

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-26272 is a medium vulnerability (CVSS 6.5) in Ckeditor, published January 26, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.35%, the 83rd percentile. Fixed in ckeditor4 4.16.0.

References

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