CVE-2026-35034Public exploitNetwork attack vector

Authenticated memory exhaustion via unlimited SyncPlay group names

Published Apr 14, 2026 · Updated Apr 14, 2026

Denial of service in Jellyfin before 10.11.7 allows remote authenticated users to exhaust server memory via oversized SyncPlay group names. The POST /SyncPlay/New endpoint accepts GroupName without a length limit, while randomized DeviceId values create unlimited concurrent sessions that retain each name in memory. Repeated requests from a single account consume RAM persistently, hang the SyncPlay group panel for other clients, and drive the process into an out-of-memory crash.

CVSS severity6.5
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Jellyfin before 10.11.7 allows remote authenticated users to exhaust server memory via oversized SyncPlay group names. The POST /SyncPlay/New endpoint accepts GroupName without a length limit, while randomized DeviceId values create unlimited concurrent sessions that retain each name in memory. Repeated requests from a single account consume RAM persistently, hang the SyncPlay group panel for other clients, and drive the process into an out-of-memory crash.

The record

CVE
CVE-2026-35034
Published
Apr 14, 2026
Updated
Apr 14, 2026
Vendor
Jellyfin
Product
Jellyfin
Classifications
CWE-400, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 10.11.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Jellyfin · Jellyfinversion=< 10.11.7

Published CVSS scores

6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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