CVE-2026-40991 Vulnerability Analysis & Exploit Details

CVE-2026-40991
Vulnerability Scoring

5.9
/10
Significant Risk

Security assessments indicate that CVE-2026-40991 presents a notable risk, potentially requiring prompt mitigation.

Attack Complexity Details

  • Attack Complexity: High
    Exploits require significant effort and special conditions.
  • Attack Vector: Network
    Vulnerability is exploitable over a network without physical access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Unchanged
    Exploit remains within the originally vulnerable component.
  • User Interaction: Required
    User interaction is necessary for successful exploitation.

CVE-2026-40991 Details

Status: Undergoing Analysis

Published on: 10 Jun 2026, 00:16 UTC

CVSS Release: version 3

CVSS3 Source

security@vmware.com

CVSS3 Type

Secondary

CVSS3 Vector

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

CVE-2026-40991 Vulnerability Summary

CVE-2026-40991: 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.

Assessing the Risk of CVE-2026-40991

Access Complexity Graph

The exploitability of CVE-2026-40991 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-40991

CVE-2026-40991 presents a challenge to exploit due to its high attack complexity, but the absence of privilege requirements still makes it a viable target for skilled attackers. A thorough security review is advised.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-40991, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-40991, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: High
    Exploiting CVE-2026-40991 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: None
    CVE-2026-40991 poses no threat to data integrity.
  • Availability: Low
    CVE-2026-40991 may slightly degrade system performance without fully affecting service availability.

CVE-2026-40991 References

External References

CWE Common Weakness Enumeration

CWE-611

CAPEC Common Attack Pattern Enumeration and Classification

  • Data Serialization External Entities Blowup CAPEC-221 This attack takes advantage of the entity replacement property of certain data serialization languages (e.g., XML, YAML, etc.) where the value of the replacement is a URI. A well-crafted file could have the entity refer to a URI that consumes a large amount of resources to create a denial of service condition. This can cause the system to either freeze, crash, or execute arbitrary code depending on the URI.

Protect Your Infrastructure against CVE-2026-40991: Combat Critical CVE Threats

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