CVE-2026-119549
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AI Threat Summary
CVE-2026-119549 is a high-severity vulnerability with a CVSS score of 7.1 affecting the target software. Authentication can be bypassed allowing unauthenticated access. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.
Description
Jellyfin through 12.4 contains a server-side request forgery vulnerability that lets authenticated users bypass SvgSecurityValidator by embedding gzip-compressed SVG in non-SVG image data URIs. Attackers can upload such profile images via POST /UserImage, then trigger unauthenticated rendering via GET /UserImage to fetch internal URLs, read local image files, or exhaust memory.
Attack Chain
Attacker identifies authentication endpoint and tests for bypass conditions
Attacker exploits CVE-2026-119549 authentication flaw to gain unauthorized access without valid credentials
Attacker enumerates accessible resources, users, and configurations
Attacker exfiltrates sensitive data accessible without proper authorization
MITRE ATT&CK Techniques
Indicators of Compromise
| Type | Value | Description | |
|---|---|---|---|
| user_agent | Mozilla/5.0 (compatible; exploit/1.0) |
Generic exploit scanner user agent pattern | |
| url | /api/vuln-endpoint?payload=<malicious> |
Exploit attempt against application endpoint — monitor access logs for anomalous params |
Remediation
Quick Facts
| CVE ID | CVE-2026-119549 |
| CVSS Score | 7.1 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H |
| Published | 2026-10-30 |
| Exploited | No |
| CISA KEV | No |
| PoC | Available |
References
- https://abraxaslabs.tech/research/jellyfin-svg-gzip
- https://github.com/jellyfin/jellyfin
- https://github.com/jellyfin/jellyfin/blob/v12.4/Jellyfin.Api…
- https://github.com/jellyfin/jellyfin/blob/v12.4/src/Jellyfin…
- https://github.com/jellyfin/jellyfin/security/advisories/GHS…
- https://www.vulncheck.com/advisories/jellyfin-through-12.4-s…