CVE-2021-39183High· 8.2▾ TwilightUnsafe inline XSS in pasting DOM element into chat
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 45.1 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 9.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
0.7%
Inline scripts are executed when Javascript is parsed via a paste action.
<img src=null onerror=alert('hello')> into the
chat field. ⋮ 13 │ // Content security policy
⋮ 14 │ csp := []string{
⋮ 15 │ "script-src 'self' 'sha256-2HPCfJIJHnY0NrRDPTOdC7AOSJIcQyNxzUuut3TsYRY='",
⋮ 16 │ "worker-src 'self' blob:", // No single quotes around blob:
⋮ 17 │ }
Will be patched in 0.0.9 by blocking unsafe-inline Content Security Policy and specifying the script-src. The worker-src is required to be set to blob for the video player.
If you have any questions or comments about this advisory:
github.com/owncast/owncast < 0.0.9Upgrade to a patched release:
github.com/owncast/owncast 0.0.9