VulnerabilityPublished 28 Nov 2025Updated 27 Jan 2026

CVE-2025-66371: Iteras Peppol-py · XML External Entity (XXE)

Affects Iteras Peppol-pySource CVE Database V5

Not known to be exploited · CVSS 5.0 Medium : upgrade to 1.1.1 when convenient.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score

5.0Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 25% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.1.1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Changed
Confidentiality: Low
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: None: The vulnerable system can be exploited without any interaction from any user.
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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
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 28 Nov 2025
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

Upgrade Iteras Peppol-py to 1.1.1.

Affected software

Product	Affected	Fixed in
PyPIpeppol-py`pkg:pypi/peppol-py`Other threats	Affected <1.1.1	Fixed in 1.1.1

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

AI-suggested

To mitigate CVE-2025-66371, organizations should immediately upgrade Peppol-py to version 1.1.1 or later, where the vulnerability is addressed by secure Saxon parser configurations that disable XML external entity processing. If upgrading is not immediately feasible, apply configuration changes to the XML parser to explicitly disable external entity resolution and DTD processing. Conduct a thorough review of all XML processing components to ensure they are not vulnerable to XXE attacks. Implement strict input validation and sanitization for all XML inputs, especially those originating from untrusted sources. Limit the privileges of the service running Peppol-py to minimize the impact of potential file disclosures. Monitor logs for unusual XML parsing activity or unexpected outbound connections that could indicate exploitation attempts. Additionally, perform regular security audits and penetration testing focused on XML processing components. Establish network segmentation and egress filtering to prevent unauthorized data exfiltration. Finally, educate developers and system administrators about secure XML handling best practices to prevent similar vulnerabilities.

Description

Peppol-py before 1.1.1 allows XXE attacks because of the Saxon configuration. When validating XML-based invoices, the XML parser could read files from the filesystem and expose their content to a remote host.

Impact

For European organizations, the impact of CVE-2025-66371 can be significant due to the extensive use of Peppol for electronic invoicing mandated or encouraged by EU regulations. Successful exploitation could lead to unauthorized disclosure of sensitive files, including financial data, internal configurations, or personally identifiable information, undermining confidentiality. This could result in regulatory non-compliance, reputational damage, and potential financial losses. Since the vulnerability does not affect integrity or availability, the primary concern is data leakage. However, the scope change indicates that the attack could impact other components or systems if the compromised files contain credentials or secrets used elsewhere. Organizations in sectors with stringent data protection requirements, such as finance, healthcare, and government, are particularly vulnerable. Additionally, attackers could leverage disclosed information for further attacks, such as lateral movement or privilege escalation. The medium severity score suggests a moderate risk, but the ease of exploitation and network accessibility increase the urgency for mitigation.

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 27 Jan 2026, 19:11 UTC

WeaknessesCWE-611

Technical details

References

Community reviews

Related threats