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OpenSearch has a bypass of REST Layer Authorization Using Malformed Paths

Low severity GitHub Reviewed Published Apr 30, 2026 in opensearch-project/security • Updated May 7, 2026

Package

maven org.opensearch.plugin:opensearch-security (Maven)

Affected versions

>= 2.11.0.0, < 2.19.0.0

Patched versions

2.19.0.0

Description

Description

A flaw was identified in the OpenSearch REST layer that could allow authorization checks to be bypassed when processing certain malformed HTTP requests. This could permit unauthorized access to restricted API endpoints in environments that rely on REST-layer authorization.

Transport-level authorization is not affected by this issue.

Impact

The default OpenSearch distribution is not affected by this issue. REST actions in the default distribution have corresponding transport actions that independently enforce authorization. Custom plugins that register REST actions without a corresponding transport action may be affected, potentially allowing unauthorized read access to those endpoints.

Patches

This issue is fixed in OpenSearch 2.19.0. Users should upgrade to 2.19.0 or later.

References

@cwperks cwperks published to opensearch-project/security Apr 30, 2026
Published to the GitHub Advisory Database May 7, 2026
Reviewed May 7, 2026
Last updated May 7, 2026

Severity

Low

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS score

Weaknesses

Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. Learn more on MITRE.

CVE ID

No known CVE

GHSA ID

GHSA-83x9-vc3c-hghc

Source code

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