Http4s up to 0.23.34/1.0.0-M46 Ember request smuggling

Summaryinfo

A vulnerability was found in Http4s up to 0.23.34/1.0.0-M46. It has been classified as problematic. This vulnerability affects unknown code of the component Ember. This manipulation causes request smuggling. This vulnerability is registered as CVE-2026-69216. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as problematic was found in Http4s up to 0.23.34/1.0.0-M46. Affected by this vulnerability is an unknown code block of the component Ember. The manipulation with an unknown input leads to a request smuggling vulnerability. The CWE definition for the vulnerability is CWE-444. The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. As an impact it is known to affect integrity. The summary by CVE is:

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, Ember’s chunk decoder trims the chunk-size token and accepts leading plus or minus signs instead of requiring one or more hexadecimal digits followed by the required CRLF. When an intermediary forwards chunked data without re-encoding and interprets malformed chunk boundaries differently, an unauthenticated attacker can create TE.TE request smuggling that bypasses intermediary controls, poisons caches, or hijacks the request queue. The same response-path leniency can enable response smuggling against an ember-client used as a gateway when the upstream is malicious or compromised. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-69216 since 08/03/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available.

Upgrading to version 0.23.35 or 1.0.0-M47 eliminates this vulnerability.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• Http4s

Version

• 0.23.0
• 0.23.1
• 0.23.2
• 0.23.3
• 0.23.4
• 0.23.5
• 0.23.6
• 0.23.7
• 0.23.8
• 0.23.9
• 0.23.10
• 0.23.11
• 0.23.12
• 0.23.13
• 0.23.14
• 0.23.15
• 0.23.16
• 0.23.17
• 0.23.18
• 0.23.19
• 0.23.20
• 0.23.21
• 0.23.22
• 0.23.23
• 0.23.24
• 0.23.25
• 0.23.26
• 0.23.27
• 0.23.28
• 0.23.29
• 0.23.30
• 0.23.31
• 0.23.32
• 0.23.33
• 0.23.34
• 1.0.0-M46

Website

• Product: https://github.com/http4s/http4s/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion