CVE-2026-100725

http4k before 6.48.0.0 Cookie Scoping Bypass via BasicCookieStorage

MEDIUM
6.5
CVSS Score
Published: September 27, 2026 at 01:28 AM UTC
Updated: September 30, 2026 at 05:32 PM UTC
1 product affected across 1 vendorHTTP4K

Using http4k by http4k?

Get instant alerts when new vulnerabilities affect http4k - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM6.5
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.51.0.0v < 5.42.0.0v < 6.48.0.0
Vendor states this is fixed in 4.51.0.0 (unaffected)
Vendor states this is fixed in 5.42.0.0 (unaffected)
Vendor states this is fixed in 6.48.0.0 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-200

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card