CVE-2026-47746Misskey: JSON-LD signature validation + compaction is vulnerable to timing attacks
Updated under an hour ago ()
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It affects misskey-dev misskey. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 8.9 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N
- Weakness (CWE)
- CWE-367
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Deferred
- Record last updated
- Aug 4, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
misskey-dev misskey misskey_dev:misskey (from the name) | from 12.37.0, < 2026.5.4 | CNA record |
References
- https://github.com/misskey-dev/misskey/security/advisories/GHSA-38jx-423m-g387x-refsource-confirm
- https://github.com/misskey-dev/misskey/releases/tag/2026.5.4x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.