CVE-2025-59822

6.3 MEDIUM 0.4% exploit odds Fix listed Other Web app

What it is

Http4s is a Scala interface for HTTP services. In versions from 1.0.0-M1 to before 1.0.0-M45 and before 0.23.31, http4s is vulnerable to HTTP Request Smuggling due to improper handling of HTTP trailer section. This vulnerability could enable attackers to bypass front-end servers security controls, launch targeted attacks against active users, and poison web caches. A pre-requisite for exploitation involves the web application being deployed behind a reverse-proxy that forwards trailer headers. This issue has been patched in versions 1.0.0-M45 and 0.23.31.

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

2025-09-23 19:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-19 16:10 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: 6.3 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2025-09-23 19:15 UTC
Last modified: 2026-10-19 16:10 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-444
Record status: Analyzed

Affected

Typelevel http4s < 0.23.31
Typelevel http4s 1.0.0

Attack profile CVSS 4.0 · 6.3

Attack vector: Network
Complexity: Low
Attack requirements: Present
Privileges needed: None
User interaction: None
Confidentiality: None
Integrity: Low
Availability: None

Raw vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-59822.md and follow it. Check whether this project is affected by CVE-2025-59822. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record