Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:LSummary
CVE-2026-40991 is a medium-severity Improper Restriction of XML External Entity Reference (CWE-611) vulnerability in Broadcom Spring Rest Docs. Its CVSS base score is 5.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 13th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to CM-6 (Configuration Settings) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-35885
Vulnerability Data
When using spring-restdocs-webtestclient or spring-restdocs-restassured to document a remote API accessed over HTTP, an attacker who compromises the API or tricks the user into documenting a malicious API can perform an XXE injection attack when the documentation-generating tests are next…
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executed. Affected versions: Spring REST Docs 4.0.0; 3.0.0 through 3.0.5; 2.0.0.RELEASE through 2.0.8.RELEASE.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
XXE (CWE-611) in HTTP-based API documentation flow directly enables exploitation of a remote/public-facing application by supplying malicious XML responses.
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation and sanitization of untrusted XML input to block external entity expansion before the Spring REST Docs test executes the malicious response.
Mandates secure configuration of XML parsers (disabling external entities/DTDs) in the test environment and dependencies, eliminating the root cause of CWE-611.
Requires integrity verification of received XML documents, allowing detection of unexpected external references introduced by a compromised remote API.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Hardened XML parser configurations directly disable external entity resolution.
Secure SDLC practices include input validation and safe XML parser configuration that prevent XXE.
Vulnerability scanning can discover XXE flaws but does not prevent their introduction in code.
Patching eliminates XXE-vulnerable parser versions but is only one aspect of software maintenance.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches XXE via static analysis and dynamic XML fuzzing.
Vulnerability management identifies and patches XML libraries with unsafe default entity settings.
Secure development life cycle mandates input validation and entity handling that directly prevents XXE.
Application security requirements explicitly call for disabling external entity processing in XML parsers.
Secure architecture principles include safe parser configuration that mitigates external entity risks.
Secure coding standards require disabling DTDs and external entities in XML processing.