CVE-2026-5388

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

Not scored by EPSS

EPSS percentile

Not scored by EPSS

NVD base score

9.3 (CVSS v4.0), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

NVD analysis status

Received. NVD last modified this record on 2026-08-23.

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

2026-08-23 13:34Z7 HR AGO

Last updated

2026-08-23 13:34Z7 HR AGO

Reserved

2026-04-01

Assigning CNA

VulnCheck

Record state

PUBLISHED

Severity

Critical (CVSS 9.3)

CNA CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Weaknesses

• CWE-20Improper Input ValidationClass

Data version

5.2

Document digest

8e2bededc3bf538ec798cebe9236d5445f4df898e7093ff2cae3d93e8430bd82

• github.comGitHub Security Advisory (GHSA-c9vm-hv86-f23r)https://github.com/EmilStenstrom/justhtml/security/advisories/GHSA-c9vm-hv86-f23rvendor-advisory
• www.vulncheck.comVulnCheck Advisory: justhtml before 1.15.0 Multiple Security Issueshttps://www.vulncheck.com/advisories/justhtml-before-multiple-security-issuesthird-party-advisory