Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2025-66482

Severity CVSS v4.0:
MEDIUM
Type:
Unavailable / Other
Publication date:
16/12/2025
Last modified:
06/01/2026

Description

Misskey is an open source, federated social media platform. Attackers who use an untrusted reverse proxy or not using a reverse proxy at all can bypass IP rate limiting by adding a forged X-Forwarded-For header. Starting with version 2025.9.1, an option (`trustProxy`) has been added in config file to prevent this from happening. However, it is initialized with an insecure default value before version 2025.12.0-alpha.2, making it still vulnerable if the configuration is not set correctly. This is patched in v2025.12.0-alpha.2 by flipping default value of `trustProxy` to `false`. Users of a trusted reverse proxy who are unsure if they manually overode this value should check their config for optimal behavior. Users are running Misskey with a trusted reverse proxy should not be affected by this vulnerability. From v2025.9.1 to v2025.11.1, workaround is available. Set `trustProxy: false` in config file.

Impact

Vector 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 6.90 MEDIUM
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): None
User Interaction (UI): None
Confidentiality (VC): None
Integrity (VI): Low
Availability (VA): Low
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None

Base Score 4.0
6.90
Severity 4.0
MEDIUM
Vector 3.x
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L CVSS v3.1 Severity and Metrics:

Base Score: 6.50 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): Low
Availability (A): Low

Base Score 3.x
6.50
Severity 3.x
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:misskey:misskey:*:*:*:*:*:*:*:* 13.1.0 (including) 2025.12.0 (excluding)
cpe:2.3:a:misskey:misskey:13.0.0:-:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta16:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta21:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta22:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta23:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta24:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta25:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta26:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta27:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta28:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta29:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta30:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta31:*:*:*:*:*:*
cpe:2.3:a:misskey:misskey:13.0.0:beta32:*:*:*:*:*:*

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools