CVE-2021-39169 json
XSS vulnerability using dialog
published 2021-08-27 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-25571
- cvss
- 8.0
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 54%
- public exploits
- 0
- none known
Summary
Misskey is a decentralized microblogging platform. In versions of Misskey prior to 12.51.0, malicious actors can use the web client built-in dialog to display a malicious string, leading to cross-site scripting (XSS). XSS could compromise the API request token. This issue has been fixed in version 12.51.0. There are no known workarounds aside from upgrading.
Patch / fix
- misskey misskey 12.51.0
Exploit prediction
0.74% chance of exploitation in the next 30 days, higher than 54% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.0 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H |
| NVD | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 3.5 | AV:N/AC:M/Au:S/C:N/I:P/A:N |
Affected products
- misskey-dev misskey
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/misskey-dev/misskey/commit/ec203f7f795766f76b55fecc9248168c1cdf6c99
patch, third-party-advisory
-
github.com
/misskey-dev/misskey/security/advisories/GHSA-pmmv-jwqh-f5ww
patch, third-party-advisory
Sources
- CVE List CVE-2021-39169
- NVD CVE-2021-39169
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