CVE-2021-4020 json
Cross-site Scripting (XSS) - Stored in meetecho/janus-gateway
published 2021-11-27 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-33923
- cvss
- 8.8
- version 3.0, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.8%
- EPSS 0.8% chance of exploitation in 30 days, percentile 58%
- public exploits
- 0
- none known
Summary
janus-gateway is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Patch / fix
- meetecho meetecho/janus-gateway 0.11.6
- janus Debian 14, Debian 12 0.11.5-4
debian advisories DEBIAN-CVE-2021-4020
Exploit prediction
0.84% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- huntr.dev https://huntr.dev/bounties/9814baa8-7bdd-4e31-a132-d9d15653409e referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.0 | 8.8 | CVSS:3.0/AV:N/AC:L/PR:L/UI:N/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
- meetecho meetecho/janus-gateway
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/meetecho/janus-gateway/commit/d3fc00ec803d6c41d8f98908732f44e7f4911a1c
patch, third-party-advisory
-
huntr.dev
/bounties/9814baa8-7bdd-4e31-a132-d9d15653409e
exploit, issue-tracking, patch, third-party-advisory
Sources
- CVE List CVE-2021-4020
- NVD CVE-2021-4020
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.