Geyser: Server-Side Request Forgery (SSRF) via Player Head Texture URL

published 2026-05-05 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-29327 , GHSA-xcfg-fcr5-gw9r

cvss: 2.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits: 0; none known

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.

Patch / fix

fixed in 3

maven org.geysermc.geyser:core 2.9.3
geysermc geyser 2.9.3
org.geysermc.geyser core 2.9.3

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 5 mo ago (2026-05-13)

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/GeyserMC/Geyser/security/advisories/GHSA-xcfg-fcr5-gw9r referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	2.4	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:N/A:N
GitHub	3.1	2.4	CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:N/A:N
NVD	3.1	4.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Affected packages

ecosystem	package	affected	fixed in
maven	org.geysermc.geyser:core	<2.9.3	2.9.3

Affected products

GeyserMC Geyser

Classification

Weakness

CWE-918 Server-Side Request Forgery

References

github.com /GeyserMC/Geyser/security/advisories/GHSA-xcfg-fcr5-gw9r
exploit, web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-42188
advisory
github.com /GeyserMC/Geyser
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary