Skip to content
Fencer Vulns
critical 9.8

CVE-2021-25827 json

Emby Server < 4.7.12.0 is vulnerable to a login bypass attack by setting the X-Forwarded-For header to a local IP-address.

published 2023-06-28 3 y ago modified 2026-10-24 16 d ago also EUVD-2021-12710

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.5%
EPSS 1.5% chance of exploitation in 30 days, percentile 74%
public exploits
0
none known

Summary

Emby Server < 4.7.12.0 is vulnerable to a login bypass attack by setting the X-Forwarded-For header to a local IP-address.

Patch / fix

  • emby emby 4.7.12.0

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
23 mo ago

Exploit prediction

1.50% chance of exploitation in the next 30 days, higher than 74% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/MediaBrowser/Emby/issues/3784 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Classification

Weakness
  • CWE-290 Authentication Bypass by Spoofing

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.