SSRF in Geyser Prior to 2.9.3 via Crafted Skin Texture URL

Publication date: 2026-05-11

Last updated on: 2026-05-11

Assigner: GitHub, Inc.

Description

Geyser is a bridge between Minecraft: Bedrock Edition and Minecraft: Java Edition. Prior to 2.9.3, a server-side request forgery (SSRF) vulnerability exists in Geyser’s handling of Bedrock player head texture data. By supplying a crafted Base64-encoded skin texture URL via the /give command, an attacker can cause the Minecraft server to issue arbitrary HTTP GET requests to attacker-controlled or internal endpoints. This occurs server-side, without proper URL validation, and can be triggered by a Bedrock client. This vulnerability is fixed in 2.9.3.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-05-11

Last Modified

2026-05-11

Generated

2026-07-11

AI Q&A

2026-05-12

EPSS Evaluated

2026-07-10

NVD

CVE-2026-42188

Affected Vendors & Products

Vendor	Product	Version / Range
geysermc	geyser	2.9.3

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-918	The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

Attack-Flow Graph

Executive Summary

This vulnerability exists in Geyser, a bridge between Minecraft: Bedrock Edition and Minecraft: Java Edition, prior to version 2.9.3. It is a server-side request forgery (SSRF) issue that occurs when Geyser handles Bedrock player head texture data. An attacker can supply a crafted Base64-encoded skin texture URL via the /give command, causing the Minecraft server to make arbitrary HTTP GET requests to attacker-controlled or internal endpoints. This happens on the server side without proper URL validation and can be triggered by a Bedrock client.

Impact Analysis

The vulnerability allows an attacker to make the Minecraft server send arbitrary HTTP GET requests to internal or attacker-controlled endpoints. This can potentially be used to access internal resources or services that are not normally exposed, leading to information disclosure or further attacks within the internal network. However, the CVSS score is relatively low (2.4), indicating limited impact, with only low confidentiality impact and no integrity or availability impact.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade Geyser to version 2.9.3 or later, where the server-side request forgery (SSRF) issue has been fixed.

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