CVE-2026-47746
TOCTOU timing flaw in Misskey JSON-LD signature verification allows forged activities.
Is CVE-2026-47746 being exploited?
Not confirmed. CVE-2026-47746 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.18% probability of exploitation in the next 30 days.
How severe is CVE-2026-47746?
CVE-2026-47746 is rated High with a CVSS score of 8.9. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-47746?
Yes. A fix has been recorded for CVE-2026-47746. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-47746 affect?
CVE-2026-47746 affects Misskey >=12.37.0 and <2026.5.4. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-47746?
Upgrade Misskey to 2026.5.4 immediately; isolate/untrust federated peers until patched.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attackers can exploit a timing race in JSON-LD signature verification to have forged activities accepted, enabling impersonation and integrity loss across federation.
Immediate action required
- affected>= 12.37.0 and < 2026.5.4
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.