CVE-2025-25299 | Cross-site scripting (XSS) in the real-time collaboration package

CKEditor 5 is a modern JavaScript rich-text editor with an MVC architecture. During a recent internal audit, a Cross-Site Scripting (XSS) vulnerability was discovered in the CKEditor 5 real-time collaboration package. This vulnerability affects user markers, which represent users' positions within the document. It can lead to unauthorized JavaScript code execution, which might happen with a very specific editor and token endpoint configuration. This vulnerability affects only installations with Real-time collaborative editing enabled. The problem has been recognized and patched. The fix is available in version 44.2.1 (and above). Users are advised to upgrade. There are no known workarounds for this vulnerability.

Published: 2025-02-20 Last update: 2026-04-15 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-25299 is rated Low Risk (29.2/100): CVSS Low severity, with medium exploitation likelihood (EPSS 0.35%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-25299

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-06 0.41% 0.35% -0.07%
2 2026-03-31 0.62% 0.41% -0.21%
3 2025-12-17 — 0.62% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-25299

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
2.3 4.0 LOW
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:P)
Additional preconditions must be present for exploitation.
Privileges required (PR:N)
No privileges are required.
User interaction (UI:P)
A user has to participate (for example click/open/approve).
Vulnerable system confidentiality impact (VC:L)
Limited confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:L)
Limited integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N)
No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.
Exploit maturity (threat) (E:X)
Not defined: no reliable threat intelligence; scoring assumes the worst case (equivalent to Attacked).
Confidentiality requirement (CR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Integrity requirement (IR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Availability requirement (AR:X)
Not defined: insufficient information; scoring treats this like High (worst case).
Modified attack vector (MAV:X)
Not defined: scoring uses the Base Attack Vector (AV).
Modified attack complexity (MAC:X)
Not defined: scoring uses the Base Attack Complexity (AC).
Modified attack requirements (MAT:X)
Not defined: scoring uses the Base Attack Requirements (AT).
Modified privileges required (MPR:X)
Not defined: scoring uses the Base Privileges Required (PR).
Modified user interaction (MUI:X)
Not defined: scoring uses the Base User Interaction (UI).
Modified vulnerable system confidentiality impact (MVC:X)
Not defined: scoring uses the Base VC metric.
Modified vulnerable system integrity impact (MVI:X)
Not defined: scoring uses the Base VI metric.
Modified vulnerable system availability impact (MVA:X)
Not defined: scoring uses the Base VA metric.
Modified subsequent system confidentiality impact (MSC:X)
Not defined: scoring uses the Base SC metric.
Modified subsequent system integrity impact (MSI:X)
Not defined: scoring uses the Base SI metric.
Modified subsequent system availability impact (MSA:X)
Not defined: scoring uses the Base SA metric.
Safety (supplemental) (S:X)
Not evaluated.
Automatable (supplemental) (AU:X)
Not evaluated.
Recovery (supplemental) (R:X)
Not evaluated.
Value density (supplemental) (V:X)
Not evaluated.
Vulnerability response effort (supplemental) (RE:X)
Not evaluated.
Provider urgency (supplemental) (U:X)
Not evaluated.
 — — [email protected]

Weakness enumeration for CVE-2025-25299

GitHub Security Advisory for CVE-2025-25299

GHSA-j3mm-wmfm-mwvh · Severity: medium · Ecosystem: npm — Cross-site scripting (XSS) in the CKEditor 5 real-time collaboration package

OS Trackers for CVE-2025-25299

vendor priority summary link
debian unimportant CVE-2025-25299 unimportant priority: Debian including 1 source packages (ckeditor), 2 status rows across 2 suites (bookworm, bullseye): resolved 2. https://security-tracker.debian.org/tracker/CVE-2025-25299
ubuntu medium CVE-2025-25299 medium priority: Ubuntu including 4 source packages (ckeditor, ckeditor3, ldap-account-manager, request-tracker4), 35 status rows across 9 suites (bionic, focal, jammy, noble, oracular, plucky, questing, upstream, xenial): needs-triage 22, ignored 12, DNE 1. https://ubuntu.com/security/CVE-2025-25299

Affected software / configurations for CVE-2025-25299

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-25299

cvelogic Threat Intelligence