CVE-2026-18954: Auth Bypass (CVSS 5.5)

Description

Incorrect authorization in the aggregation pipeline tool in Amazon AWS Labs DocumentDB MCP Server before 1.0.12 might allow an authenticated MCP client to perform inappropriate write operations on the connected database via write-capable aggregation pipeline stages that bypass the read-only mode enforcement logic. To remediate this issue, users should upgrade to version 1.0.12 or later.

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CVSS v3.1 Score

5.5

MEDIUM

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

EPSS — Exploit Prediction

0.0011

Probability of exploitation

0.01%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-863 Incorrect Authorization

References

Other References

https://aws.amazon.com/security/security-bulletins/2026-076-aws/ https://github.com/awslabs/mcp/releases/tag/2026.04.20260408085348

Frequently Asked Questions

What is CVE-2026-18954? +

Incorrect authorization in the aggregation pipeline tool in Amazon AWS Labs DocumentDB MCP Server before 1.0.12 might allow an authenticated MCP client to perform inappropriate write operations on the connected database via write-capable aggregation pipeline stages that bypass the read-only mode enforcement logic. To remediate this issue, users should upgrade to version 1.0.12 or later. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2026-18954? +

CVE-2026-18954 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0011, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-18954? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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