CVSS scoring

Prisma Cloud leverages the CVSS 3.1 scoring system and normalizes severity ratings into a common schema as the severity terminology can vary between projects. The CVSS framework captures the principal characteristics of a vulnerability and produces a numerical score that reflects the severity of the vulnerability. CVSS scores range from 0.0 to 10.0. The higher the number, the higher the degree of severity.

• For known vulnerabilities with a CVE, Prisma Cloud relies on the most authoritative source.
• For OS packages (packages that are maintained by the OS vendor, marked as type “package” in Compute), the CVE details are from the specific vendor feed.
• For other CVEs, the information is from official sources like NVD and vendor-specific security advisories.
• If the affected package is maintained by an OS vendor, the severity as indicated by the vendor is used and not the severity determined by NVD. Furthermore, for new vulnerabilities missing analysis, or undocumented vulnerabilities (such as PRISMA-IDs), Prisma Cloud uses the severity rating as determined by our threat researchers.

Mappings

We only normalize vulnerability ratings for the purpose of creating rules. Prisma Console Monitoring section shows the predefined rankings as for Critical, High, Medium severity, and not the vendor defined terminologies.

Note: The “unimportant”, “unassigned”, “untriaged”, “negligible” and “not yet assigned” severity reporting name will remain the same as defined by the vendors.

The following table maps popular vendor terminology to Prisma Cloud normalized rankings:

Vendor terminology	Prisma Cloud score	Vendors
Unimportant	Unimportant	*Debian *SUSE
Unassigned	Unassigned
Negligible	Negligible	Ubuntu
Not yet assigned	Not yet assigned
Low	Low
UnTriaged	UnTriaged	Ubuntu
Medium	Medium	*Oracle *Red Hat Enterprise Linux *Rocky *Suse *Windows Server
Moderate	Medium	*Oracle *Red Hat Enterprise Linux *Rocky *Suse *Windows Server
High	High
Important	High	*Amazon *Oracle *Red Hat Enterprise Linux *Rocky *SUSE *Ubuntu
Critical	Critical	*Alpine * Amazon Linux container image * Amazon Linux *BusyBox *CentOS *Debian *Red Hat Enterprise Linux *SUSE *Ubuntu (LTS releases only) *Windows Server *Chainguard Wolfi Linux
end-of-life Note: 'end-of-life' will be set in the vulnerability status	Low, Medium, High, or Critical based on NVD.	Debian

NOTE: In the absence of project-specific terminology, Prisma Cloud normalizes using the CVSS base scores defined by NIST. In addition to the numeric CVSS scores, NVD provides severity rankings of Low, Medium, High, and Critical.

These qualitative grades are simply derived from the numeric CVSS scores:

CVSS base score	Prisma Cloud severity
0.0 - 3.9	Low
4.0 - 6.9	Medium
7.0 - 8.9	High
9.0 -10.0	Critical

In some cases, the OS vendor’s CVSS scoring and severity rating can differ from NVD’s rating. This is based on the vendor’s analysis of the impact of the CVE specific to their OS and distro, which is the more accurate view of the vulnerability. Prisma Cloud shows the vendor’s rating when reporting findings from workloads running the vendor’s OS, and falls back to NVD’s rating where applicable.

Example: CVE-2021-33574 has a CVSS 3.0 score of 9.8 and it’s graded as 'critical' by NVD. The same CVE is graded as 'low' by Ubuntu and 'medium' with a different CVSS score by Redhat. For workloads running Ubuntu, Prisma Cloud shows Ubuntu’s rating, rather than NVD’s rating.