Is CVE-2021-21402 actively exploited?

Yes. CVE-2021-21402 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, which means exploitation in the wild has been confirmed.

Can CVE-2021-21402 be exploited remotely?

The attack vector of CVE-2021-21402 has not been classified yet.

What is the CVSS score of CVE-2021-21402?

CVE-2021-21402 has not received a CVSS score yet.

HOME VULNERABILITIESCVE-2021-21402

UNKNOWNCISA KEVIN THE WILD

CVE-2021-21402

Published: April 11, 2026

EPSS:90.47%probability of exploitation in 30 daysPercentile:99.6th

Official Description

Jellyfin is a Free Software Media System. In Jellyfin before version 10.7.1, with certain endpoints, well crafted requests will allow arbitrary file read from a Jellyfin server's file system. This issue is more prevalent when Windows is used as the host OS. Servers that are exposed to the public Internet are potentially at risk. This is fixed in version 10.7.1. As a workaround, users may be able to restrict some access by enforcing strict security permissions on their filesystem, however, it is recommended to update as soon as possible.

NVD Source

Technical Analysis

CVE-2021-21402 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

CISA has added CVE-2021-21402 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.