Spring Web Services XXE via Unsafe XPath Evaluation

Jaxp13XPathTemplate evaluated XPath expressions for StreamSource and SAXSource inputs using a code path that parsed attacker-controlled XML with the JDK's default DocumentBuilderFactory behavior instead of Spring's hardened parser configuration. Applications that evaluate XPath against untrusted XML payloads could therefore be exposed to XML External Entity (XXE) style attacks. Affected versions: Spring Web Services 5.0.0 through 5.0.1; 4.1.0 through 4.1.3; 4.0.0 through 4.0.18; 3.1.0 through 3.1.8.

Casky was already ahead

This CVE exploits attack patterns that Casky's 301matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

This vulnerability stems from improper XML parsing in Spring Web Services' Jaxp13XPathTemplate component, which fails to apply Spring's hardened parser configuration when evaluating XPath expressions against StreamSource and SAXSource inputs. Instead, it defaults to the JDK's DocumentBuilderFactory with XXE protections disabled, allowing attackers to inject malicious XML entities that can lead to data exfiltration, denial of service, or server-side request forgery. The vulnerability affects multiple versions across Spring Web Services 3.1.0 through 5.0.1, creating a broad attack surface for organizations processing untrusted XML documents through XPath evaluation workflows.

Casky's 301 matched skills enable practitioners to identify XXE attack patterns (CWE-611) by analyzing how applications handle XML parsing and XPath processing. Using Claude's extended reasoning with MITRE ATT&CK mappings (TA0001: Initial Access and TA0043: Reconnaissance), practitioners can detect reconnaissance probes testing for XXE susceptibility, followed by exploitation attempts injecting external entity declarations. In findings, practitioners would see skill-driven detections flagging unsafe DocumentBuilderFactory instantiation, missing XXE feature disablement (such as disabled DTD processing or external entity resolution), and anomalous XML payloads containing entity definitions targeting sensitive files or internal services. These pattern-based detections allow security teams to pinpoint vulnerable XPath evaluation code paths before exploitation occurs.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

301 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-40998.

analyzing-apt-group-with-mitre-navigator

threat intelligence · low

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analyzing-campaign-attribution-evidence

threat intelligence · low

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analyzing-certificate-transparency-for-phishing

threat intelligence · low

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MITRE ATT&CK Techniques

TA0001 TA0043

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