CVE-2021-4020

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

0.84% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 57.6% of scored records. A rank, not a probability.

NVD base score

5.4 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2021-11-27 09:15Z4 YR AGO

Last updated

2024-08-03 17:16Z2 YR AGO

Reserved

2021-11-25

Assigning CNA

@huntrdev

Record state

PUBLISHED

Severity

High (CVSS 8.8)

CNA CVSS vector

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weaknesses

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')Base

Data version

5.1

Document digest

33d4ee3b4e5c670ead4a01e5ead6adeb4b904882776a6026357d08f88c89e3fe

• huntr.devhttps://huntr.dev/bounties/9814baa8-7bdd-4e31-a132-d9d15653409ex_refsource_CONFIRM
• github.comhttps://github.com/meetecho/janus-gateway/commit/d3fc00ec803d6c41d8f98908732f44e7f4911a1cx_refsource_MISC