CVE-2025-59822: Http4s is a Scala interface for HTTP services

Q: How do I fix CVE-2025-59822?

http4s: upgrade to 0.23.31. Exact commands for each OS are on this page.

Q: Is CVE-2025-59822 being exploited?

CVE-2025-59822 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-59822 affect?

CVE-2025-59822 affects http4s. Severity is high (CVSS 7.5). 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 enabl

Q: How urgent is CVE-2025-59822?

Priority 44/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2025-59822 is a high-severity flaw (CVSS 7.5) affecting http4s. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 behin

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 69%)
CISA exploited list	No
Weakness	CWE-444
Published	2025-09-23
Last modified	2026-10-19

Publisher (CNA): GitHub, Inc. · Vendor: typelevel

Last updated 2026-10-19 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-09-23 19:15 UTCPublished CVE record published
2026-10-19 16:10 UTCUpdated Record last modified

typelevel http4s UPGRADE

Affected: < 0.23.31 · 1.0.0 milestone1 · 1.0.0 milestone10 · 1.0.0 milestone11 · 1.0.0 milestone12 · 1.0.0 milestone13 · 1.0.0 milestone14 · 1.0.0 milestone15

Fixed in: 0.23.31

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy http4s || rpm -q http4s || http4s --version

2. UPGRADE to 0.23.31 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade http4s

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade http4s

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-59822?

http4s: upgrade to 0.23.31. Exact commands for each OS are on this page.

Is CVE-2025-59822 being exploited?

CVE-2025-59822 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-59822 affect?

CVE-2025-59822 affects http4s. Severity is high (CVSS 7.5). 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 enabl

How urgent is CVE-2025-59822?

Priority 44/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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