XSS in Owncast
CVE-2021-39183
Owncast is an open source, self-hosted live video streaming and chat server. In affected versions inline scripts are executed when Javascript is parsed via a paste action. This issue is 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.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:H/A:L.
EPSS exploit prediction
EPSS: 0.007 (53.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 53.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000
Affected products
- Owncast — versions < 0.0.9
- Owncast Project
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/owncast/owncast/security/advisories/GHSA-2hfj-cxw7-g45p (Exploit, Patch, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-39183?
- CVE-2021-39183 is a high-severity vulnerability in Owncast, classified under Cross-site Scripting. CVSS score: 8.2/10. Published 2021-12-14.
- How severe is CVE-2021-39183?
- High severity. CVSS v3 base score is 8.2 out of 10.
- Is CVE-2021-39183 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.