CVE-2021-25827

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.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://emby.media/community/index.php?/topic/98191-emby-server-46-released/	Product
https://github.com/EmbySupport/security/security/advisories/GHSA-fffj-6fr6-3fgf	Not Applicable
https://github.com/MediaBrowser/Emby/issues/3784	Exploit Issue Tracking Third Party Advisory
https://emby.media/community/index.php?/topic/98191-emby-server-46-released/	Product
https://github.com/EmbySupport/security/security/advisories/GHSA-fffj-6fr6-3fgf	Not Applicable
https://github.com/MediaBrowser/Emby/issues/3784	Exploit Issue Tracking Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:emby:emby:*:*:*:*:*:*:*:*

History

24 Oct 2026, 13:10

Type	Values Removed	Values Added
Summary		(es) Emby Servidor anterior a 4.7.12.0 es vulnerable a un ataque de omisión de inicio de sesión al establecer la cabecera X-Forwarded-For a una dirección IP local.

Information

Published : 2023-06-28 20:15

Updated : 2026-10-24 13:10

NVD link : CVE-2021-25827

Mitre link : CVE-2021-25827

CVE.ORG link : CVE-2021-25827

JSON object : View

Products Affected

emby

emby

CWE

CWE-290

Authentication Bypass by Spoofing

{"id": "CVE-2021-25827", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2021-25827", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2024-12-03T16:50:24.601886Z"}}], "cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 3.9}]}, "affected": [{"source": "cve@mitre.org", "affectedData": [{"vendor": "n/a", "product": "n/a", "versions": [{"status": "affected", "version": "n/a"}]}]}], "published": "2023-06-28T20:15:09.397", "references": [{"url": "https://emby.media/community/index.php?/topic/98191-emby-server-46-released/", "tags": ["Product"], "source": "cve@mitre.org"}, {"url": "https://github.com/EmbySupport/security/security/advisories/GHSA-fffj-6fr6-3fgf", "tags": ["Not Applicable"], "source": "cve@mitre.org"}, {"url": "https://github.com/MediaBrowser/Emby/issues/3784", "tags": ["Exploit", "Issue Tracking", "Third Party Advisory"], "source": "cve@mitre.org"}, {"url": "https://emby.media/community/index.php?/topic/98191-emby-server-46-released/", "tags": ["Product"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://github.com/EmbySupport/security/security/advisories/GHSA-fffj-6fr6-3fgf", "tags": ["Not Applicable"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://github.com/MediaBrowser/Emby/issues/3784", "tags": ["Exploit", "Issue Tracking", "Third Party Advisory"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-290"}]}], "descriptions": [{"lang": "en", "value": "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."}, {"lang": "es", "value": "Emby Servidor anterior a 4.7.12.0 es vulnerable a un ataque de omisi\u00f3n de inicio de sesi\u00f3n al establecer la cabecera X-Forwarded-For a una direcci\u00f3n IP local."}], "lastModified": "2026-10-24T13:10:00.147", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:emby:emby:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "D8269B6B-081E-4BA9-BF1F-92730FFD72F5", "versionEndExcluding": "4.7.12.0"}], "operator": "OR"}]}], "sourceIdentifier": "cve@mitre.org"}