CVE-2021-23155

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

0.47% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 38.3% of scored records. A rank, not a probability.

NVD base score

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

NVD CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/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

2021-11-18 17:58Z4 YR AGO

Last updated

2024-09-17 00:21Z1 YR AGO

Reserved

2021-01-26

Assigning CNA

Gallagher

Record state

PUBLISHED

Severity

Critical (CVSS 9.0)

CNA CVSS vector

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

Weaknesses

• CWE-296Improper Following of a Certificate's Chain of TrustBase
• CWE-295Improper Certificate ValidationBase

Data version

5.1

Document digest

9fa31971b0eadedc3b14948d5bf77139226c1fefafc6b790bb151671673a23e3

• security.gallagher.comhttps://security.gallagher.com/Security-Advisories/CVE-2021-23155x_refsource_MISC