Vulnerability in Http4s

CVE-2026-69215

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, The CookieJar client middleware uses unanchored substring checks instead of RFC 6265 domain and path matching when deciding whether to attach a stored cookie. A cookie for example.com can consequently be sent to an attacker-controlled hostname such as evilexample.com when an application using the same jar makes an attacker-influenced outbound request. This exposes session or authentication cookies and can enable hijacking of the application’s outbound sessions. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.005 (43.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-69215: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

  • Http4s — versions < 0.23.35, >= 1.0.0-M1, < 1.0.0-M47

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-69215?
CVE-2026-69215 is a medium-severity vulnerability in Http4s, classified under Reliance on Cookies without Validation and Integrity Checking. CVSS score: 6.8/10. Published 2026-09-15.
How severe is CVE-2026-69215?
Medium severity. CVSS v3 base score is 6.8 out of 10.