How severe is CVE-2025-59822?

CVE-2025-59822 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2025-59822 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-59822?

CVE-2025-59822 primarily affects Typelevel Http4s. In total, 45 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-59822?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-59822 have an EU (EUVD) identifier?

Yes. CVE-2025-59822 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-30898.

When was CVE-2025-59822 published?

CVE-2025-59822 was published on 2025-09-23 and last updated on 2026-06-17.

CVE-2025-59822

CVE-2025-59822 is a high-severity vulnerability in Typelevel Http4s with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-444.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 6.3
EPSS exploit prediction: 0% (27th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-30898
Weakness: CWE-444
Affected product: Typelevel Http4s
Published: 2025-09-23
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2025-59822?: 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.
How severe is CVE-2025-59822?: CVE-2025-59822 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2025-59822 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-59822?: CVE-2025-59822 primarily affects Typelevel Http4s. In total, 45 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-59822?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-59822 have an EU (EUVD) identifier?: Yes. CVE-2025-59822 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-30898.
When was CVE-2025-59822 published?: CVE-2025-59822 was published on 2025-09-23 and last updated on 2026-06-17.

References

Affected products (45)

cpe:2.3:a:typelevel:http4s:*:*:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone1:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone10:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone11:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone12:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone13:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone14:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone15:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone16:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone17:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone18:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone19:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone2:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone20:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone21:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone22:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone23:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone24:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone25:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone26:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone27:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone28:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone29:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone3:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone30:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone31:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone32:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone33:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone34:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone35:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone36:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone37:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone38:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone39:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone4:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone40:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone41:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone42:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone43:*:*:*:*:*:*
cpe:2.3:a:typelevel:http4s:1.0.0:milestone44:*:*:*:*:*:*

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