CVE-2021-4124

Cross-site Scripting (XSS) - Stored in meetecho/janus-gateway

8.1 High

janus-gateway is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Attack profile

How easy it is to exploit

Attack vector: Adjacent network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: High
Availability: High

Exploit likelihood

0.97%Up 0.3 points since Dec 17, 2021

What each source reports

CVE List Score used 8.1

Cross-site Scripting (XSS) - Stored in meetecho/janus-gateway

janus-gateway is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: CVE-2021-4124
CVSS 3.0: 8.1 HighCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Weakness: CWE-79
Updated: 2026-11-02

EUVDEUVD-2021-33998 8.1

janus-gateway is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: EUVD-2021-33998
CVSS 3.0: 8.1 HighCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Updated: 2026-11-03

GitHub AdvisoriesGHSA-gv3q-27qx-g2xh No score

janus-gateway is vulnerable to Improper Neutralization of Input During Web Page Generation (...

janus-gateway is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: GHSA-gv3q-27qx-g2xh
Weakness: CWE-79
Updated: 2026-11-02

NVD 6.1

janus-gateway is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: CVE-2021-4124
CVSS 3.1: 6.1 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS 3.0: 8.1 HighCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CVSS 2.0: 4.3 MediumAV:N/AC:M/Au:N/C:N/I:P/A:N
Weakness: CWE-79
Updated: 2026-11-02

OSV 6.1

janus-gateway is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: CVE-2021-4124
CVSS 3.1: 6.1 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Updated: 2026-11-02

OSVDEBIAN-CVE-2021-4124 6.1

janus-gateway is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: DEBIAN-CVE-2021-4124
CVSS 3.1: 6.1 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Updated: 2026-11-02

OSVUBUNTU-CVE-2021-4124 6.1

janus-gateway is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Record: UBUNTU-CVE-2021-4124
CVSS 3.1: 6.1 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS 3.0: 8.1 HighCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`janus` Debian:12	All versions, plus listed versions 1.1.2-11.1.2-1.11.1.2-1.21.1.2-21.1.2-3 Show 6 moreShow less 1.1.2-3.11.1.2-41.4.1+ds-11.4.1+ds-21.4.1+ds-31.4.1+ds-4	None known
`janus` Debian:14	All versions, plus listed versions 0.10.0-10.10.1-10.10.2-10.10.3-10.10.4-1 Show 45 moreShow less 0.10.5-10.10.6-10.10.7-10.10.8-10.10.8-20.10.9-10.10.9-20.11.1-10.11.2-10.11.3-1~exp10.11.4-10.11.5-10.11.5-20.11.5-30.11.5-40.11.6-10.11.6-1~bpo11+10.11.7-10.11.7-1~bpo11+10.11.8-10.11.8-1~bpo11+10.11.8-20.11.8-30.11.8-3~bpo11+10.12.0-10.2.2+dfsg-10.2.2+dfsg-20.2.2+dfsg-30.2.2+dfsg-40.2.2+dfsg-5~exp10.2.2+dfsg-5~exp20.2.2+dfsg-5~exp30.2.3-10.2.4-10.2.4-20.2.5-10.2.6-10.3.1-10.4.2-10.4.4-10.4.5-10.4.5-20.5.0-10.6.0-10.6.0-2	None known
`janus` Ubuntu:18.04:LTS	All versions, plus listed versions 0.2.4-20.2.5-10.2.6-10.2.6-1build10.2.6-1build2	None known
`janus` Ubuntu:20.04:LTS	All versions, plus listed versions 0.7.3-20.7.3-2build1	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-4124 is a high vulnerability (CVSS 8.1) in Meetecho Janus, published December 16, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.97%, the 62nd percentile. No source names a fixed version.

References

This page doesn't list everything

Left out here: 36 versions. The JSON record has them.