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.
Metrics
Affected Vendors & Products
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History
Wed, 16 Sep 2026 14:30:00 +0000
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ssvc
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Tue, 15 Sep 2026 22:30:00 +0000
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Http4s
Http4s http4s |
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Http4s
Http4s http4s |
Tue, 15 Sep 2026 19:15:00 +0000
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| Description | 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. | |
| Title | Http4s: Ember chunk parser lenience (TE.TE request smuggling) | |
| Weaknesses | CWE-444 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-09-15T18:59:50.609Z
Updated: 2026-09-16T13:53:52.337Z
Reserved: 2026-08-03T16:57:50.125Z
Link: CVE-2026-69216
Updated: 2026-09-16T13:53:46.246Z
Status : Deferred
Published: 2026-09-15T19:17:38.603
Modified: 2026-09-16T20:39:16.610
Link: CVE-2026-69216
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