CVE-2021-29953

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

0.64% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 50.8% of scored records. A rank, not a probability.

NVD base score

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

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/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

Critical. Red Hat's rating for its own products, not a CVSS rating.

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

2021-06-24 13:17Z5 YR AGO

Last updated

2024-08-03 22:18Z2 YR AGO

Reserved

2021-04-01

Assigning CNA

mozilla

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

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

Data version

5.1

Document digest

7b6353ed44b0d2f817bf1e55a46e7fcad775500640d86dca6c52b8b4f20bb4cf

• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2021-20/x_refsource_MISC
• bugzilla.mozilla.orghttps://bugzilla.mozilla.org/show_bug.cgi?id=1701684x_refsource_MISC