CVE-2026-47746 Misskey: JSON-LD signature validation + compaction is vulnerable to timing attacks
Attackers can exploit timing attacks in JSON-LD validation to bypass integrity checks and submit fraudulent activities as valid.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-47746?
CVE-2026-47746 is a high-severity vulnerability in misskey-dev misskey, published on 3 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Misskey is an open source, federated social media platform. Versions 12.37.0 and later, but prior to 2026.5.4, are vulnerable to timing attacks during JSON-LD signature validation and the compaction process. Because the JSON-LD parsing context is not shared between signature verification and subsequent processing, the application may trust information that should not be trusted, resulting in a time-of-check to time-of-use (TOCTOU) flaw. This allows an attacker to have fraudulent activities accepted as valid, leading to a loss of integrity. This issue has been fixed in version 2026.5.4.
Weakness: CWE-367
Which versions are affected by CVE-2026-47746?
How do I fix CVE-2026-47746?
No fix has been published for CVE-2026-47746 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-47746 being exploited?
There is no known exploitation of CVE-2026-47746 in the wild and no public exploit code.
Sources
Also known as GHSA-38jx-423m-g387.