Information disclosure in Http4k
CVE-2026-100725
http4k (Maven artifact org.http4k:http4k-core) before 6.48.0.0, 5.42.0.0, and 4.51.0.0 ships a BasicCookieStorage (client-side cookie store used by ClientFilters.Cookies) that does not enforce RFC 6265 scoping rules for the cookie domain, path, and Secure attributes. When a single BasicCookieStorage instance is used to talk to more than one origin or scheme, cookies stored for one origin can be sent to other origins, and cookies marked Secure can be sent over plain HTTP, potentially disclosing session cookies or other sensitive values to unauthorized hosts or network observers. Clients that use a storage instance for a single origin are not affected.
Vulnerability class: Information Disclosure
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (15.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 15th percentile — 15.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
Weakness classification (CWE)
References
- GitHub Security Advisory (GHSA-pr33-38xx-6r26) (vendor-advisory)
- Patch Commit (patch)
- VulnCheck Advisory: http4k before 6.48.0.0 Cookie Scoping Bypass via BasicCookieStorage (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100725?
- CVE-2026-100725 is a medium-severity vulnerability in Http4k, classified under Information Disclosure. CVSS score: 6.5/10. Published 2026-09-27.
- How severe is CVE-2026-100725?
- Medium severity. CVSS v3 base score is 6.5 out of 10.