In Eclipse AAS4J before 3.0.1, `XmlSchemaValidator.validateSchema()` (and `AASXValidator.validateSchema()`, which calls it) validates untrusted XML with a default JAXP `Validator` that resolves external DTDs and external entities. An attacker who supplies a crafted AAS XML document or AASX package can read local files from the host, send their contents out-of-band to an attacker-controlled server, and make the validating process send arbitrary outbound requests (SSRF). Validation still returns no errors.
Details:
- Vulnerable code: `dataformat-xml/src/main/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/xml/XmlSchemaValidator.java`. `schema.newValidator().validate(new StreamSource(...))` runs without `ACCESS_EXTERNAL_DTD` / `ACCESS_EXTERNAL_SCHEMA` restrictions and without `disallow-doctype-decl`.
- Second entry point: `dataformat-aasx/src/main/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/AASXValidator.java`. The AAS XML part of an `.aasx` package is passed unchanged to the vulnerable validator.
- `XmlDeserializer` (Jackson/Woodstox) is not affected, because DTD support is disabled by default there.
- Present since the initial import of the code base (commit `cc9da52`).
- Fix: harden the validator by setting `ACCESS_EXTERNAL_DTD` and `ACCESS_EXTERNAL_SCHEMA` to `\"\"` and rejecting `DOCTYPE` declarations. The bundled `AAS.xsd` does not need DTDs, so no functionality is lost.
"}],"value":"In Eclipse AAS4J before 3.0.1, `XmlSchemaValidator.validateSchema()` (and `AASXValidator.validateSchema()`, which calls it) validates untrusted XML with a default JAXP `Validator` that resolves external DTDs and external entities. An attacker who supplies a crafted AAS XML document or AASX package can read local files from the host, send their contents out-of-band to an attacker-controlled server, and make the validating process send arbitrary outbound requests (SSRF). Validation still returns no errors.\n\n\n\nDetails:\n\n\n\n- Vulnerable code: `dataformat-xml/src/main/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/xml/XmlSchemaValidator.java`. `schema.newValidator().validate(new StreamSource(...))` runs without `ACCESS_EXTERNAL_DTD` / `ACCESS_EXTERNAL_SCHEMA` restrictions and without `disallow-doctype-decl`.\n\n\n\n- Second entry point: `dataformat-aasx/src/main/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/AASXValidator.java`. The AAS XML part of an `.aasx` package is passed unchanged to the vulnerable validator.\n\n\n\n- `XmlDeserializer` (Jackson/Woodstox) is not affected, because DTD support is disabled by default there.\n\n\n\n- Present since the initial import of the code base (commit `cc9da52`).\n\n\n\n- Fix: harden the validator by setting `ACCESS_EXTERNAL_DTD` and `ACCESS_EXTERNAL_SCHEMA` to `\"\"` and rejecting `DOCTYPE` declarations. The bundled `AAS.xsd` does not need DTDs, so no functionality is lost."}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":7.7,"baseSeverity":"HIGH","exploitMaturity":"NOT_DEFINED","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"providerMetadata":{"dateUpdated":"2026-11-13T14:31:30.855Z","orgId":"e51fbebd-6053-4e49-959f-1b94eeb69a2c","shortName":"eclipse"},"references":[{"url":"https://github.com/eclipse-aas4j/aas4j"},{"url":"https://github.com/eclipse-aas4j/aas4j/blob/main/dataformat-xml/src/main/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/xml/XmlSchemaValidator.java"},{"url":"https://gitlab.eclipse.org/security/cve-assignment/-/work_items/571"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.5"}}},"cveMetadata":{"assignerOrgId":"e51fbebd-6053-4e49-959f-1b94eeb69a2c","assignerShortName":"eclipse","cveId":"CVE-2026-127031","datePublished":"2026-11-13T14:28:08.365Z","dateReserved":"2026-11-12T10:50:53.618Z","dateUpdated":"2026-11-13T14:31:30.855Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-11-13 15:17:44","lastModifiedDate":"2026-11-13 15:17:44","problem_types":[],"metrics":{"cvssMetricV40":[{"source":"emo@eclipse.org","type":"Secondary","cvssData":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/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","baseScore":7.7,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"127031","Ordinal":"1","Title":"CVE-2026-127031","CVE":"CVE-2026-127031","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"127031","Ordinal":"1","NoteData":"In Eclipse AAS4J before 3.0.1, `XmlSchemaValidator.validateSchema()` (and `AASXValidator.validateSchema()`, which calls it) validates untrusted XML with a default JAXP `Validator` that resolves external DTDs and external entities. An attacker who supplies a crafted AAS XML document or AASX package can read local files from the host, send their contents out-of-band to an attacker-controlled server, and make the validating process send arbitrary outbound requests (SSRF). Validation still returns no errors.\n\n\n\nDetails:\n\n\n\n- Vulnerable code: `dataformat-xml/src/main/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/xml/XmlSchemaValidator.java`. `schema.newValidator().validate(new StreamSource(...))` runs without `ACCESS_EXTERNAL_DTD` / `ACCESS_EXTERNAL_SCHEMA` restrictions and without `disallow-doctype-decl`.\n\n\n\n- Second entry point: `dataformat-aasx/src/main/java/org/eclipse/digitaltwin/aas4j/v3/dataformat/aasx/AASXValidator.java`. The AAS XML part of an `.aasx` package is passed unchanged to the vulnerable validator.\n\n\n\n- `XmlDeserializer` (Jackson/Woodstox) is not affected, because DTD support is disabled by default there.\n\n\n\n- Present since the initial import of the code base (commit `cc9da52`).\n\n\n\n- Fix: harden the validator by setting `ACCESS_EXTERNAL_DTD` and `ACCESS_EXTERNAL_SCHEMA` to `\"\"` and rejecting `DOCTYPE` declarations. The bundled `AAS.xsd` does not need DTDs, so no functionality is lost.","Type":"Description","Title":"CVE-2026-127031"}]}}}