CVE-2026-35031Disclosure(jellyfin / jellyfin)

LOWCVSS 8.8 · HIGH

Exploit discussion active in current signal (1 latest mentions)

Immediate actions

Hunt for exploitation attempts and persistence artifacts
Increase monitoring for publicly documented tradecraft
Track advisory updates for patch or workaround availability

Recommended action window: High priority (within 72h)

NVD description

Jellyfin is an open source self hosted media server. Versions prior to 10.11.7 contain a vulnerability chain in the subtitle upload endpoint (POST /Videos/{itemId}/Subtitles), where the Format field is not validated, allowing path traversal via the file extension and enabling arbitrary file write. This arbitrary file write can be chained into arbitrary file read via .strm files, database extraction, admin privilege escalation, and ultimately remote code execution as root via ld.so.preload. Exploitation requires an administrator account or a user that has been explicitly granted the "Upload Subtitles" permission. This issue has been fixed in version 10.11.7. If users are unable to upgrade immediately, they can grant non-administrator users Subtitle upload permissions to reduce attack surface.

jellyfin CVEs Back to dashboard

1.5/ 10 priority

Sources & remediation

Vendor / third-party advisories

https://github.com/jellyfin/jellyfin/security/advisories/GHSA-j2hf-x4q5-47j3

Other references

https://github.com/jellyfin/jellyfin/releases/tag/v10.11.7

Weakness type (CWE)

CWE-20CWE-22CWE-187

Priority

LOW

Exploitation

NONE

PoC

YES

Patch

NONE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

jellyfin

Threat summary

Public PoC is present in monitored signal
6 mentions across 3 observed days
Momentum state: stable

What's happening

PoC mentioned or linked in 1 signal
Technical details provided in 5 signals
Disclosure: 4 classified signals
General: 2 classified signals
Peaked 2d ago at 4 mentions (2026-04-15); latest day: 1
6 total mentions across 3 days

Affected systems

Vendors

jellyfin

Products

jellyfin

Deep dive

Activity timeline6 mentions / 3d

Signal classification2 categories

Disclosure

466.7%

General

233.3%

Referenced assets6 URLs

By indicator

Classification over time

Date	Total	Labels

2026-04-15	4	Disclosure3General1
2026-04-16	1	Disclosure1
2026-04-18	1	General1

Full discourse6 posts

Kerem 🛡 Cyber Security Engineer@keraattin177d
Disclosure
a critical RCE discovered in Jellyfin Media Server (CVE-2026-35031, CVSS 9.9). The subtitle upload endpoint doesn't validate the format field, allowing path traversal + arbitrary file write. This chains into database extraction, admin escalation, and root RCE. A 5-minute read thread below...
Post summary
The post announces the discovery of a critical remote code execution flaw in Jellyfin Media Server, outlining the attack vector and potential impact, but does not provide a PoC, exploit code, patch, or evidence of active exploitation.
1000094
1.1K followersView on X
IntegSec@integ_sec175d
General
CVE-2026-35031: Jellyfin Subtitle Upload Path Traversal Vulnerability - What It Means for Your Business and How to Respond https://hubs.li/Q04cCCCS0
Post summary
The available text only contains a headline about Jellyfin’s path‑traversal vulnerability, with no details on PoC, exploitation, patches, or technical specifics.
0000039
29 followersView on X
0day Signal@0dayPublishing176d
Disclosure
🚨 CVE-2026-35031: Jellyfin: Potential RCE via subt... Subtitle upload to root RCE via path traversal + .strm file chaining is a beautiful exploit primitive that turns media ... https://zerodaysignal.com/vulnerability/CVE-2026-35031 #netsec #vulnerability #CVE #sysadmin #zeroday
Post summary
The tweet announces a Jellyfin vulnerability (CVE-2026-35031) that can lead to remote code execution via path traversal and .strm file chaining, with a link suggesting a proof of concept exists.
0000085
218 followersView on X
CTIWatch@ctiwatchcloud178d
General
🔍 Today's Top Vulnerabilities 🔴 CVE-2026-35031 | CVSS 9.9 🔴 CVE-2026-38526 | CVSS 9.9 🔴 CVE-2025-63939 | CVSS 9.8 🔗 http://ctiwatch.cloud/vulnerabilities #CVE #Vulnerability #ThreatIntel
Post summary
The tweet lists three high‑CVSS CVEs and a link to a vulnerability portal, but does not include PoC, exploit details, active exploitation, or patch information.
00000302
5.6K followersView on X
CVE@CVEnew178d
Disclosure
CVE-2026-35031 Jellyfin is an open source self hosted media server. Versions prior to 10.11.7 contain a vulnerability chain in the subtitle upload endpoint (POST /Videos/{itemId}/Su… https://www.cve.org/CVERecord?id=CVE-2026-35031
Post summary
The text announces a known vulnerability in Jellyfin versions before 10.11.7, detailing its location in the subtitle upload endpoint, but does not provide PoC, exploit, patch, or evidence of active exploitation.
00000104
57.2K followersView on X
Vulmon Vulnerability Feed@VulmonFeeds178d
Disclosure
CVE-2026-35031 Arbitrary File Write and Remote Code Execution in Jellyfin Prior ... https://vulmon.com/vulnerabilitydetails?qid=CVE-2026-35031 Vulnerability Alert Subscriptions: https://alerts.vulmon.com/?utm_source=twitter&utm_medium=social&utm_campaign=2102281&utm_content=1
Post summary
The tweet announces a newly identified vulnerability (CVE-2026-35031) in Jellyfin that permits arbitrary file writes and remote code execution, providing a link to details but no PoC, exploit code, or mitigation.
0000047
4.0K followersView on X

CPE platform detail1 entries

Part:

Vendor:

Product:

Version:

Target SW:

Target HW:

1 of 1 entries

Part	Vendor	Product	Version	Target SW	Target HW
App	jellyfin	jellyfin	-	-	-

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What researchers are saying

CVE-2026-35031

Kerem 🛡 Cyber Security Engineer[verified]@keraattinDisclosure

The post announces the discovery of a critical remote code execution flaw in Jellyfin Media Server, outlining the attack vector and potential impact, but does not provide a PoC, exploit code, patch, or evidence of active exploitation.

IntegSec[verified]@integ_secGeneral

The available text only contains a headline about Jellyfin’s path‑traversal vulnerability, with no details on PoC, exploitation, patches, or technical specifics.

0day Signal@0dayPublishingDisclosure

The tweet announces a Jellyfin vulnerability (CVE-2026-35031) that can lead to remote code execution via path traversal and .strm file chaining, with a link suggesting a proof of concept exists.

CTIWatch@ctiwatchcloudGeneral

The tweet lists three high‑CVSS CVEs and a link to a vulnerability portal, but does not include PoC, exploit details, active exploitation, or patch information.

CVE@CVEnewDisclosure

The text announces a known vulnerability in Jellyfin versions before 10.11.7, detailing its location in the subtitle upload endpoint, but does not provide PoC, exploit, patch, or evidence of active exploitation.

Vulmon Vulnerability Feed@VulmonFeedsDisclosure

The tweet announces a newly identified vulnerability (CVE-2026-35031) in Jellyfin that permits arbitrary file writes and remote code execution, providing a link to details but no PoC, exploit code, or mitigation.