Time-of-check Time-of-use (TOCTOU) Race Condition in Misskey - CVE-2026-47746
Published: May 23, 2026
Vulnerability identifier: #VU132176
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-47746
CWE-ID: CWE-367
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Misskey Development Division
Affected software:
Misskey
Misskey
Detailed vulnerability description
The vulnerability allows a remote attacker to cause integrity loss.
The vulnerability exists due to a time-of-check time-of-use race condition in JSON-LD signature validation and compaction process when processing JSON-LD activities. A remote attacker can submit specially crafted activities to cause integrity loss.
The issue occurs because the context used for JSON-LD parsing is not shared between signature verification and actual processing, which can result in fake activities being accepted as valid.
How to mitigate CVE-2026-47746
Install security update from vendor's website.