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CVE-2026-42188 Geyser

Affected softwareGeyser
Severity4.3 Medium CVSS 3.1 2 scores
Fixed in2.9.3
WeaknessServer-side request forgery (CWE-918)
Published11 May 2026
Updated26 Oct 2026

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.

Exploitation status

Proof of concept only

A proof of concept exists, but no reviewed exploit catalogue lists this CVE.

  • CISA KEV not listed
  • VulnCheck KEV not listed
  • CISA Vulnrichment exploitation: poc CISA recorded that an exploit has been demonstrated. Automatable: no, technical impact: partial.
  • Indexed PoC none indexed
  • EPSS 0.19% chance in 30 days

Waratek protection

Outside Waratek scope

A Java vulnerability, but not one Waratek protects. It affects only Java on a user's desktop (applets, Web Start, JavaFX, the installer), sits in a product the Waratek agent can't be installed into, or is in a package we don't expect in business applications. The decision below says which.

  • Protection none
  • Action not pursued none
  • Review automated Upstream data
  • Record active
Decided by An OSV.dev record of this CVE affecting a package published to Maven Central. When every such package is one business applications do not use (Minecraft mods and launchers, Fastjson) and no tracked product is named by CPE, it settles the CVE as Outside Waratek scope instead
Finding Every Maven package this CVE affects (org.geysermc.geyser:core) is on the excluded_maven_packages list in known-products.yaml, so it is not reviewed.

CVSS

4.3 MEDIUM v3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N 2 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

VersionScoreBandVectorAssignerType
CVSS 3.1 4.3 MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N NVD Primary published
CVSS 3.1 2.4 LOW CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:N/A:N security-advisories@github.com Secondary

Affected software and releases

Maven packages

Affected and fixed versions, from OSV.dev
PackageIntroducedFixedLast affected
org.geysermc.geyser:core 0 2.9.3 unbounded

Products and versions

2 products, 2 version entries
SourceVendorProductSchemeAffected versions
nvd geysermc geyser generic < 2.9.3
osv org.geysermc.geyser core generic < 2.9.3

References

URLTags
https://github.com/GeyserMC/Geyser/security/advisories/GHSA-xcfg-fcr5-gw9r WEB
https://github.com/GeyserMC/Geyser PACKAGE

Timeline

Published2026-05-11By the CVE Program.
NVD record modified2026-10-26NVD's own last-modified date for this record.