CVE-2026-69216

5.4 MEDIUM 0.4% exploit odds Fix listed Other

What it 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.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-09-15 19:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-09-16 20:39 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 5.4 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-09-15 19:17 UTC
Last modified: 2026-09-16 20:39 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-444
Record status: Deferred

Attack profile CVSS 3.1 · 5.4

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None
Scope: Changed
Confidentiality: Low
Integrity: Low
Availability: None

Raw vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

Is it in your code?

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Fix and advisories

References

NVD record · CVE.org record