What is the CVSS score of CVE-2026-72657?

CVE-2026-72657 has a CVSS 3.1 base score of 6.5 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N. EPSS exploitation probability: 0.3%.

Fleet Server CVE-2026-72657

EUVD-2026-58280 MEDIUM

Authorization Bypass Through User-Controlled Key (CWE-639)

2026-08-13 elastic

GHSA-4ppv-hgww-58v5

Authentication Bypass Information Disclosure Elastic Fleet Server

6.5

CVSS 3.1 · Vendor: elastic

Severity by source

Vendor (elastic) PRIMARY

6.5 MEDIUM

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

vuln.today AI

6.5 MEDIUM

PR:L confirmed by requirement for enrolled agent credential; C:H for policy content exposure; I:N and A:N as exploitation enables read-only unauthorized access only.

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

4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (elastic).

CVSS VectorVendor: elastic

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Lifecycle Timeline

Analysis Generated

Aug 13, 2026 - 20:12 vuln.today

DescriptionCVE.org

Authorization Bypass Through User-Controlled Key (CWE-639) in Fleet Server can lead to information disclosure via Manipulating User-Controlled Variables (CAPEC-77). The authorization decision for artifact downloads relied on a client-supplied value that was persisted without being validated against the server-side record of the requesting agent's assignment. An authenticated party in possession of a valid enrolled agent credential could therefore retrieve a policy the agent is not assigned to.

AnalysisAI

Policy information disclosure in Elastic Fleet Server allows any enrolled agent with valid credentials to retrieve policy documents it was not assigned to by substituting a client-controlled key in artifact download requests. The authorization decision relied on a client-supplied value that was persisted without being cross-checked against the server-side record of the requesting agent's actual policy assignment - a textbook CWE-639 flaw. The CVSS 3.1 score of 6.5 (AV:N/AC:L/PR:L/UI:N) reflects network-accessible, low-complexity exploitation by any authenticated agent; no public exploit has been identified at time of analysis, and the vulnerability is not listed in CISA KEV.

Technical ContextAI

Elastic Fleet Server is the orchestration component of the Elastic Stack responsible for managing Elastic Agent enrollments, policy distribution, and artifact delivery at scale. The affected code path handles artifact downloads, where the authorization logic accepted a client-supplied identifier (likely a policy ID or related key) that was persisted server-side without validation against the agent's actual assigned policy record. This satisfies CWE-639 (Authorization Bypass Through User-Controlled Key): the server treats a client-controlled value as authoritative for access control rather than independently resolving the requesting agent's entitlements. The attack technique maps to CAPEC-77 (Manipulating User-Controlled Variables), requiring only that the caller substitute a target policy identifier in the controlled field. The CPE cpe:2.3:a:elastic:fleet_server:*:*:*:*:*:*:*:* indicates the wildcard affects all Fleet Server versions prior to the patched releases identified in ESA-2026-112.

RemediationAI

Upgrade Elastic Fleet Server to the patched versions identified in security advisory ESA-2026-112 available at https://discuss.elastic.co/t/fleet-server-8-19-20-9-4-5-9-5-1-security-update-esa-2026-112/389509 - the advisory URL slug implies fixed versions in the 8.19.x, 9.4.5, and 9.5.1 release lines, but the authoritative fixed versions must be confirmed from the advisory page directly; do not infer exact patch versions from the URL alone. As a compensating control prior to patching, restrict network access to Fleet Server artifact download endpoints using firewall rules or network segmentation, limiting reachability to trusted agent subnets only - this raises the effective attack complexity without altering Fleet Server configuration. Additionally, audit enrolled agent inventories and revoke credentials for any agents that are no longer active or are operated by untrusted parties, since exploitation requires a valid enrolled-agent credential.