CVE-2025-66482: Misskey is an open source, federated social media platform

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MEDIUM 6.5REMOTEUPGRADE

CVE-2025-66482 is a medium-severity flaw (CVSS 6.5) affecting misskey. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 73%)
CISA exploited list	No
Weakness	CWE-307, CWE-1188
Published	2025-12-16
Last modified	2026-10-14

Publisher (CNA): GitHub, Inc. · Vendor: misskey

Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-12-16 00:16 UTCPublished CVE record published
2026-10-14 13:10 UTCUpdated Record last modified

misskey misskey UPGRADE

Affected: >= 13.1.0 and < 2025.12.0 · 13.0.0 · 13.0.0 beta16 · 13.0.0 beta21 · 13.0.0 beta22 · 13.0.0 beta23 · 13.0.0 beta24 · 13.0.0 beta25

Fixed in: 2025.12.0

Safe to downgrade to: a release before 13.0.0

1. Check installed version

apt-cache policy misskey || rpm -q misskey || misskey --version

2. UPGRADE to 2025.12.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade misskey

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade misskey

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 13.0.0 (Debian / Ubuntu)

apt-cache madison misskey sudo apt install misskey=<VERSION_BEFORE_13.0.0> sudo apt-mark hold misskey

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list misskey sudo dnf downgrade misskey-<VERSION_BEFORE_13.0.0> sudo dnf versionlock add misskey

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-66482?

misskey: upgrade to 2025.12.0. Exact commands for each OS are on this page.

Is CVE-2025-66482 being exploited?

CVE-2025-66482 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-66482 affect?

CVE-2025-66482 affects misskey. Severity is medium (CVSS 6.5). 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

How urgent is CVE-2025-66482?

Priority 40/100. Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-66402 MEDIUM 6.5 UPGRADE Misskey is an open source, federated social media platform
CVE-2026-28433 MEDIUM 4.3 UPGRADE Misskey is an open source, federated social media platform
CVE-2026-28432 HIGH 7.5 UPGRADE Misskey is an open source, federated social media platform
CVE-2026-28431 HIGH 7.5 UPGRADE Misskey is an open source, federated social media platform
CVE-2025-25306 CRITICAL 9.3 UPGRADE Misskey is an open source, federated social media platform

References

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