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MEDIUM severity

CVE-2026-40991 — spring-restdocs-webtestcl…

MEDIUM

CVE-2026-40991 is a medium-severity (CVSS 5.9) XML External Entity (XXE) vulnerability in org.springframework.restdocs:spring-restdocs-webtestclient. A fix is available for org.springframework.restdocs:spring-restdocs-webtestclient — see the affected versions and patch details below.

XML External Entity (XXE) injection when documenting untrusted XML content

Also known asGHSA-6rpq-6vv2-5222
Published
Jun 9, 2026
Updated
Aug 12, 2026
Affected
6 pkgs
Patched
4 / 6
Exploits
None indexed
Exploitation data as of Sep 26, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40991.

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs20th percentile — riskier than 20% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-40991 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

6 pkgs affected
☕org.springframework.restdocs:spring-restdocs-webtestclient☕org.springframework.restdocs:spring-restdocs-webtestclient☕org.springframework.restdocs:spring-restdocs-webtestclient☕org.springframework.restdocs:spring-restdocs-restassured☕org.springframework.restdocs:spring-restdocs-restassured☕org.springframework.restdocs:spring-restdocs-restassured

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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 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.

Affected Packages

6 total 4 fixed
EcosystemPackageVulnerable rangeFix
☕Mavenorg.springframework.restdocs:spring-restdocs-webtestclient≥ 4.0.0&&< 4.0.14.0.1org.springframework.restdocs:spring-restdocs-webtestclient:4.0.1
☕Mavenorg.springframework.restdocs:spring-restdocs-webtestclient≥ 3.0.0&&< 3.0.63.0.6org.springframework.restdocs:spring-restdocs-webtestclient:3.0.6
☕Mavenorg.springframework.restdocs:spring-restdocs-webtestclientall versionsNo fix
☕Mavenorg.springframework.restdocs:spring-restdocs-restassured≥ 4.0.0&&< 4.0.14.0.1org.springframework.restdocs:spring-restdocs-restassured:4.0.1
☕Mavenorg.springframework.restdocs:spring-restdocs-restassured≥ 3.0.0&&< 3.0.63.0.6org.springframework.restdocs:spring-restdocs-restassured:3.0.6
☕Mavenorg.springframework.restdocs:spring-restdocs-restassuredall versionsNo fix

Affected Products

1 product · 3 configurations
Application
spring rest docsbroadcom
≥ 3.0.0 && < 3.0.5.1
1 version
4.0.0

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.springframework.restdocs:spring-restdocs-webtestclient, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update org.springframework.restdocs:spring-restdocs-webtestclient to 4.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40991 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

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 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.
O3 Security · Impact-Aware SCA

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