SunEditor before 3.4.0 Stored XSS via DocumentType Header textContent
- Exploited
- No known exploitation
- Fix
- Fixed in 3.4.0
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. SunEditor version before 3.4.0 (affected versions up to 3.3.1) Editor configured with type 'document:header' (or 'document:header,page')
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 21/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
SunEditor before 3.4.0 contains a stored cross-site scripting vulnerability in the DocumentType constructor that injects header textContent into innerHTML without HTML escaping. Attackers can store entity-encoded HTML in h1-h6 headers that executes JavaScript when editors using document:header mode initialize, enabling session cookie theft.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure12/25Specific setups only, reachable over the network without a login
- Reach?/20Unknown. No tracked technology or package matched
- Severity9.3/10CVSS 9.3
- No patch0/5No signal
What would change the score
- Would score about 71 if added to CISA KEV
- Would score about 66 if CISA's SSVC rates exploitation active
What to do
Check whether your setup matches what the bug needs.
SunEditor version before 3.4.0 (affected versions up to 3.3.1) Editor configured with type 'document:header' (or 'document:header,page')Upgrade to a fixed version: 3.4.0.
Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
Affected versions
- JiHong88 suneditor
fixed in 3.4.0
Evidence 2
- Advisory
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-124493
Is CVE-2026-124493 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
SunEditor's DocumentType module does not properly sanitize header text, so text saved there can carry attacker-supplied JavaScript. When a victim views that content, the script runs in their browser and can steal session cookies and act as the victim.Source: vulncheck.com, github.com
Which versions are affected by CVE-2026-124493?
suneditor: before 3.4.0.Source: cve.now feed data
Am I affected, and how do I check?
Versions of suneditor before 3.4.0 (affected versions up to 3.3.1) are affected, but only when the editor is configured with type 'document:header' or 'document:header,page'. To check, look at the installed suneditor package version and search the editor setup for the type option.Source: vulncheck.com, github.com
How do I fix CVE-2026-124493?
Upgrade suneditor to 3.4.0 or later, which contains the fix.Source: vulncheck.com, github.com