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NVD / CVE Program· CNA GitHub_M

CVE-2021-32808: Cross-site scripting in ckeditor via abuse of undo functionality

Noroxi assessment

Priority: Monitor (action score 21/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1.1% (FIRST EPSS); higher than 67.8% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: ckeditor (Debian:12) 4.16.2+dfsg-1; ckeditor4 (npm) 4.16.2.
  • Severity is disputed: the assigning authority (CNA) scores it 7.6, NVD 5.4.

Low priority for now. Upgrade to ckeditor (Debian:12) 4.16.2+dfsg-1; ckeditor4 (npm) 4.16.2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

ckeditor is an open source WYSIWYG HTML editor with rich content support. A vulnerability has been discovered in the clipboard Widget plugin if used alongside the undo feature. The vulnerability allows a user to abuse undo functionality using malformed widget HTML, which could result in executing JavaScript code. It affects all users using the CKEditor 4 plugins listed above at version >= 4.13.0. The problem has been recognized and patched. The fix will be available in version 4.16.2.

MediumCVSS 5.4 · v3.1—No exploit Fix available
Published
Aug 12, 2021
Updated
Jun 16, 2026
EPSS
1.1% · 67th percentile

Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.1%

CNA vs NVD score

NVD
5.4
CNA · GitHub_M
7.6
2.2 point gap

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
ckeditorckeditor
fedoraprojectfedora
oracleapplication express
oraclebanking party management
oraclecommerce guided search
oraclecommerce merchandising
oracledocumaker
oraclefinancial services analytical applications infrastructure
oraclefinancial services model management and governance
oraclejd edwards enterpriseone tools
oraclepeoplesoft enterprise peopletools
oraclesiebel ui framework

and 1 more

Is the CKEditor 4 on your site affected?

The free JavaScript library scanner reads the CKEditor 4 version from the files your site loads, matches this record and other known vulnerabilities, and gives the safe version on the same branch. If the version can't be read, it says so. No account needed.

Scan JavaScript libraries

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • ckeditor ckeditor4.13.0 and later · before 4.16.2
  • fedoraproject fedora33
  • fedoraproject fedora34
  • fedoraproject fedora35
  • oracle application expressbefore 21.1.4
  • oracle banking party management2.7.0
  • oracle commerce guided search11.3.2
  • oracle commerce merchandising11.3.2
  • oracle documaker12.6.3
  • oracle documaker12.6.4
  • oracle financial services analytical applications infrastructure8.0.7 and later · up to 8.1.1 inclusive
  • oracle financial services model management and governance8.0.8.0.0
  • oracle financial services model management and governance8.1.0.0.0
  • oracle jd edwards enterpriseone toolsup to 9.2.6.0 inclusive
  • oracle peoplesoft enterprise peopletools8.57
  • oracle peoplesoft enterprise peopletools8.58
  • oracle peoplesoft enterprise peopletools8.59
  • oracle siebel ui frameworkup to 21.9 inclusive
  • oracle webcenter sites12.2.1.3.0
  • oracle webcenter sites12.2.1.4.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • ckeditor ckeditor4

    • >= 4.13.0, < 4.16.2affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12ckeditorbefore 4.16.2+dfsg-14.16.2+dfsg-1
npmckeditor4from 4.13.0 · before 4.16.24.16.2

Same product

ckeditor: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-31541A unrestricted file upload vulnerability was discovered in the ‘Browse and upload images’ feature of the CKEditor v1.2.3 plugin for Redmine,
    39Monitor
  • CVE-2022-24729Regular expression Denial of Service in dialog plugin
    31Monitor
  • CVE-2011-4972hook_file_download in the CKEditor module 7.x-1.4 for Drupal does not properly restrict access to private files, which allows remote attacke
    31Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2021-26272Jan 26, 2021 · 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
    27Monitor
  • ← EarlierCVE-2021-33829Jun 9, 2021 · A cross-site scripting (XSS) vulnerability in the HTML Data Processor in CKEditor 4 4.14.0 through 4.16.x before 4.16.1 allows remote attack
    25Monitor
  • Later →CVE-2021-32809Aug 12, 2021 · Arbitrary HTML injection vulnerability in ckeditor
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:ckeditor4.16.2+dfsg-1 · Debian:12Package registry (OSV)
npm:ckeditor44.16.2Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality impact
Low
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

nvd-primary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records