CVE-2023-4421

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

0.76% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 55.1% of scored records. A rank, not a probability.

NVD base score

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

NVD CVSS vector

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

NVD analysis status

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

Red Hat severity

Moderate. 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

2023-12-12 17:02Z2 YR AGO

Last updated

2025-11-04 19:25Z11 MO AGO

Reserved

2023-08-18

Assigning CNA

mozilla

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

• CWE-203Observable DiscrepancyBase
• CWE-208Observable Timing DiscrepancyBase

Data version

5.2

Document digest

4e1eb1ca4d75e422baf8f6c3373628b5d887a564c6c54a2d0907fc22428e7503

• bugzilla.mozilla.orghttps://bugzilla.mozilla.org/show_bug.cgi?id=1651411
• www.mozilla.orghttps://www.mozilla.org/security/advisories/mfsa2023-53/
• lists.debian.orghttps://lists.debian.org/debian-lts-announce/2023/10/msg00039.html