5.9

CVE-2026-87913: aws aws security agent mcp server Unverified Ownership

CVSS: 5.9v3.1MediumAwaiting analysis
Published 10-09-2026Last modified 10-09-2026
Open JSON

Vulnerability summary

CVE-2026-87913 is a medium (CVSS 5.9) Unverified Ownership vulnerability in aws aws security agent mcp server. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 37% of scored vulnerabilities.

Overall risk
24/100
0100
Low · default modelHow is this calculated?
CVSS score
5.9/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.44%
0%100%
Low · +0.19 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 10-09-2026
    PublishedVulnerability first disclosed.
  2. 10-09-2026
    Last modifiedVulnerability information updated.

Description

A missing S3 bucket ownership verification in the AWS Security Agent MCP server before 0.2.0 version might allow remote attackers to obtain the private source archive of a scanned workspace, including credentials and infrastructure state contained in that archive, via a pre-registered storage bucket whose name is derived from a publicly known account identifier. To remediate this issue, users should upgrade to version 0.2.0. Users should also verify that the scan output bucket in their account is owned by their own account, because upgrading does not release a bucket name that a third party has already registered.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.44%

Chance of exploitation in the next 30 days

Percentile

37%

Versus all other CVEs

30-day change

+0.19 pp

From 0.25% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.44%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Aws1 product

1 vendor · 1 product

References

3 links