VulnerabilityPublished 3 Feb 2026

CVE-2026-23795: Apache Syncope · XML External Entity (XXE)

Affects Apache SyncopeSource CVE Database V5

Not known to be exploited · CVSS 4.9 Medium · fixed in 3.0.16 : update Apache Syncope when convenient.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

4.9Medium

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

EPSS: 1.9% chance of exploitation in 30 days – higher than 79% 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:H/UI:N/S:U/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: High
User Interaction: None
Scope: Unchanged
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: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
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-console`pkg:maven/Apache Software Foundation/org.apache.syncope.client.idrepo:syncope-client-idrepo-console`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

Immediate upgrade to Apache Syncope versions 3.0.16 or 4.0.4, which contain patches that properly restrict XML external entity processing.
Restrict administrative access to the Syncope Console to trusted personnel only and enforce strong authentication mechanisms such as multi-factor authentication (MFA).
Implement network segmentation and monitoring to detect unusual access patterns or data exfiltration attempts related to the Syncope server.
Conduct regular audits of Keymaster parameters and XML configurations to identify any unauthorized or suspicious changes.
Employ XML parsing libraries or configurations that disable external entity resolution by default, and validate all XML inputs rigorously.
Monitor security advisories and threat intelligence feeds for any emerging exploit code or attack campaigns targeting this vulnerability.
Incorporate this vulnerability into incident response plans to ensure rapid containment if exploitation is suspected. These measures go beyond generic patching by focusing on access control, monitoring, and secure XML handling practices tailored to the affected product and environment.

Description

Improper Restriction of XML External Entity Reference vulnerability in Apache Syncope Console. An administrator with adequate entitlements to create or edit Keymaster parameters via Console can construct malicious XML text to launch an XXE attack, thereby causing sensitive data leakage occurs. 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, the impact of CVE-2026-23795 can be significant, especially for those relying on Apache Syncope for identity and access management. Exploitation could lead to unauthorized disclosure of sensitive configuration data, credentials, or other internal information, potentially enabling further attacks such as privilege escalation or lateral movement within networks. This could compromise the confidentiality of personal data protected under GDPR, leading to regulatory penalties and reputational damage. Critical sectors such as finance, healthcare, government, and telecommunications, which often use identity management solutions, may face operational disruptions or data breaches. The requirement for administrative privileges limits the attack surface but insider threats or compromised administrator accounts could be leveraged by attackers. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits once the vulnerability is public. Therefore, the vulnerability poses a medium to high risk to European entities depending on their deployment and security posture.

CWE-611Improper Restriction of XML External Entity Reference (opens in a new tab)
Base weaknessOWASP Top 10 A02:2025: Security Misconfiguration (opens in a new tab)
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
Implementation · System Configuration
Many XML parsers and validators can be configured to disable external entity expansion.
OWASP Cheat Sheets
Deserialization (opens in a new tab)
XML Security (opens in a new tab)
XML External Entity Prevention (opens in a new tab)
OWASP ASVS 4.0.3
V5.5.2 (opens in a new tab)
Attack patterns
Data Serialization External Entities Blowup (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

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

WeaknessesCWE-611

Technical details

References

Community reviews

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