CVE-2025-66482

CVE-2025-66482 is a medium-severity vulnerability in Misskey with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-307.

Key facts

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.

Frequently asked questions

What is CVE-2025-66482?
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.
How severe is CVE-2025-66482?
CVE-2025-66482 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability low.
Is CVE-2025-66482 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-66482?
CVE-2025-66482 primarily affects Misskey. In total, 37 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-66482?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-66482 have an EU (EUVD) identifier?
Yes. CVE-2025-66482 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-203441.
When was CVE-2025-66482 published?
CVE-2025-66482 was published on 2025-12-16 and last updated on 2026-06-17.

References

Affected products (37)

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