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CVE-2026-27707

7.3 · HIGH

Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby.

Published Feb 27, 2026CWE-288EPSS 0.70%

Overview

CVE-2026-27707 is a high-severity vulnerability. It was published on February 27, 2026 and has a CVSS 3.1 base score of 7.3 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.3, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

Seerr is an open-source media request and discovery manager for Jellyfin, Plex, and Emby. Starting in version 2.0.0 and prior to version 3.1.0, an authentication guard logic flaw in `POST /api/v1/auth/jellyfin` allows an unauthenticated attacker to register a new Seerr account on any Plex-configured instance by authenticating with an attacker-controlled Jellyfin server. The attacker receives an authenticated session and can immediately use the application with default permissions, including the ability to submit media requests to Radarr/Sonarr. Any Seerr deployment where all three of the following are true may be vulnerable: `settings.main.mediaServerType` is set to `PLEX` (the most common deployment).; `settings.jellyfin.ip` is set to `""` (default, meaning Jellyfin was never configured); and `settings.main.newPlexLogin` is set to `true` (default). Jellyfin-configured and Emby-configured deployments are not affected. Version 3.1.0 of Seerr fixes this issue.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/seerr-team/seerr/commit/4ae20684092b5b28527b23dfbc1a3417858fee8eGitHubgithub.com/seerr-team/seerr/releases/tag/v3.1.0GitHubgithub.com/seerr-team/seerr/security/advisories/GHSA-rc4w-7m3r-c2f7

How CyberStrike helps

Frequently asked questions

What is CVE-2026-27707?

CVE-2026-27707 is a high-severity vulnerability. It was published on February 27, 2026 and has a CVSS 3.1 base score of 7.3 (HIGH).

How severe is CVE-2026-27707?

This vulnerability has a CVSS 3.1 base score of 7.3, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-27707?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-27707?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-27707 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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