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01 Record

CVE-2026-18430

HumHub 1.18.4 - Stored XSS in comment-deletion notifications through unescaped administrator reason

HighPUBLISHEDCNA: Fluid Attacks
CNA base score7.2 CVSS v4.0CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N

02 Description

HumHub 1.18.4 - Stored XSS in comment-deletion notifications through unescaped administrator reason

03 Exploitation and scoring

Exploitation
Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
SSVC decision
  • ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.46% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 40.2% of scored records. A rank, not a probability.
NVD base score
7.2 (CVSS v4.0), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/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
Deferred. NVD last modified this record on 2026-10-27.
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.

04 Metadata

Published
2026-08-19 15:52Z2 MO AGO
Last updated
2026-08-19 19:21Z2 MO AGO
Reserved
2026-07-30
Assigning CNA
Fluid Attacks
Record state
PUBLISHED
Severity
High (CVSS 7.2)
CNA CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N
Weaknesses
  • CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')Base
Data version
5.2
Document digest
857a1fc11a0355f95d995ffb60d0528f7bd8b5de42d5ed07a59eedd94b336df7

05 Affected products

VendorProductVersionsPlatforms
HumHubHumHub1.18.4Windows, MacOS, Linux

06 References