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.

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)

EPSS: 0.007 (51.1th percentile) — read the EPSS interpretation.

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.

Affected products

Owncast — versions < 0.0.9
Owncast_project Owncast

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

References

security-advisories@github.com (x_refsource_CONFIRM, 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.