VulnerabilityPublished 3 Feb 2026

CVE-2026-23794: Apache Syncope · Cross-site Scripting

Affects Apache SyncopeSource CVE Database V5

Not known to be exploited · CVSS 6.8 Medium · fixed in 3.0.16 : update Apache Syncope when convenient.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

6.8Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.5% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.0.16

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: Required
Scope: Changed
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Apache Software FoundationApache Syncope	Affected >=3.0 <=3.0.15 >=4.0 <=4.0.3	Fixed in–
Mavenorg.apache.syncope/syncope`pkg:maven/org.apache.syncope/syncope`Other threats	Affected =3.0 =4.0	Fixed in–
MavenApache Software Foundation/org.apache.syncope.client.idrepo:syncope-client-idrepo-common-ui`pkg:maven/Apache Software Foundation/org.apache.syncope.client.idrepo:syncope-client-idrepo-common-ui`Other threats	Affected >=3.0 <=3.0.15 >=4.0 <=4.0.3	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should immediately upgrade Apache Syncope installations to versions 3.0.16 or 4.0.4, which contain the official patches for this vulnerability. In addition to patching, organizations should implement strict Content Security Policies (CSP) to restrict the execution of unauthorized scripts in browsers. Web Application Firewalls (WAFs) can be configured to detect and block suspicious input patterns indicative of reflected XSS attempts targeting the login page. User awareness training should emphasize the risks of clicking on unsolicited or suspicious links, especially those purporting to lead to login portals. Logging and monitoring should be enhanced to detect anomalous login attempts or unusual URL parameters. For environments where immediate patching is not feasible, consider restricting access to the Syncope Enduser portal via VPN or IP whitelisting to reduce exposure. Regular security assessments and penetration tests should include checks for XSS vulnerabilities in critical web applications.

Description

Reflected XSS in Apache Syncope's Enduser Login page. An attacker that tricks a legitimate user into clicking a malicious link and logging in to Syncope Enduser could steal that user's credentials. This issue affects Apache Syncope: from 3.0 through 3.0.15, from 4.0 through 4.0.3. Users are recommended to upgrade to version 3.0.16 / 4.0.4, which fix this issue.

Impact

For European organizations, this vulnerability poses a significant risk to the confidentiality and integrity of user credentials managed through Apache Syncope. Identity management systems are critical infrastructure components that control access to various enterprise resources. Exploitation could lead to unauthorized access, lateral movement within networks, and potential data breaches. Given the GDPR and other stringent data protection regulations in Europe, a compromise resulting from this vulnerability could lead to regulatory penalties and reputational damage. Organizations in sectors such as finance, healthcare, government, and telecommunications, which often rely on robust identity management solutions, are particularly at risk. The ease of exploitation through social engineering increases the threat, especially in environments with less user security awareness. Although no known exploits are currently active, the vulnerability's presence in widely used versions means that unpatched systems remain exposed.

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (XSS) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Feb 2026, 15:44 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

Related threats