CVE-2026-69215

Http4s: CookieJar middleware matches by substring, leaking cookies cross-origin

MEDIUM
6.8
CVSS Score
Published: September 15, 2026 at 07:17 PM UTC
Updated: September 16, 2026 at 08:54 PM UTC
1 product affected across 1 vendorHTTP4S

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Severity
MEDIUM6.8
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

Description

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.

Affected

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

v < 0.23.35v < 1.0.0-M47
Affected range stops below 0.23.35, so it looks safe — our inference, not a vendor statement
Affected range stops below 1.0.0-M47, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

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

CVSS

6.8MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-565CWE-1275

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