Vulnerability · Published Aug 19, 2026 · Assigned by Fluid Attacks
CVE-2026-18526HumHub 1.18.4 / 1.18.4-pl1 – Stored Cross-Site Scripting in oEmbed confirmation
High 7.4
In plain English
A high-severity cross-site scripting in HumHub from HumHub. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities).
Severity (CVSS 4.0)7.4High
Exploit odds (30 days)0.5%top 60.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
HumHub Community Edition 1.18.4 and 1.18.4-pl1 contain a stored Cross-Site Scripting (XSS) vulnerability in the oEmbed confirmation rendering workflow.
Affected products (as reported)
Weakness: CWE-79 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N
References
- https://fluidattacks.com/advisories/greeicy third-party-advisory
- https://github.com/humhub/humhub product
- https://github.com/humhub/humhub/pull/8373 patch