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CVE-2023-22465 Http4s

Affected softwareHttp4s
Severity7.5 High CVSS 3.1 2 scores
Fixed in0.21.34, 0.22.15, 0.23.17, 1.0.0-M38
WeaknessImproper input validation (CWE-20)
Published4 Jan 2023
Updated17 Jun 2026

Description

Http4s is a Scala interface for HTTP services. Starting with version 0.1.0 and prior to versions 0.21.34, 0.22.15, 0.23.17, and 1.0.0-M38, the User-Agent and Server header parsers are susceptible to a fatal error on certain inputs. In http4s, modeled headers are lazily parsed, so this only applies to services that explicitly request these typed headers. Fixes are released in 0.21.34, 0.22.15, 0.23.17, and 1.0.0-M38. As a workaround, use the weakly typed header interface.

Exploitation status

Proof of concept only

A proof of concept exists, but no reviewed exploit catalogue lists this CVE.

  • CISA KEV not listed
  • VulnCheck KEV not listed
  • CISA Vulnrichment exploitation: poc CISA recorded that an exploit has been demonstrated. Automatable: yes, technical impact: partial.
  • Indexed PoC none indexed
  • EPSS 0.89% chance in 30 days

Waratek protection

No exploit published

Within Waratek scope. In the sources we check, nobody has published exploit code for this CVE or reported it being exploited.

A public code fix exists.

  • Protection none
  • Action unverified
  • Review automated Upstream data
  • Record active
Decided by Exploit code for this candidate, published in a reviewed catalogue or a GitHub repository with 5 or more stars, or in use per CISA or VulnCheck; not only a CISA verdict, a forecast, or nothing at all
Finding This CVE is not listed in CISA KEV or VulnCheck KEV, CISA Vulnrichment records no active exploitation, no reviewed exploit catalogue carries an entry for it, and no GitHub PoC repository for it has 5 or more stars. Nobody has published exploit code worth tracing, so it is not a candidate for a rule ahead of the ones where somebody has; an upstream fix path does exist, so the remediation half of the candidacy still holds. This is a statement about what has been published, not about whether the defect is reachable or serious.
Candidate fix https://github.com/http4s/http4s/security/advisories/GHSA-54w6-vxfh-fw7f : the maintainers' own security advisory: names the version that fixes it, so the fix is the difference between two releases

CVSS

7.5 HIGH v3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H 2 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

VersionScoreBandVectorAssignerType
CVSS 3.1 7.5 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H security-advisories@github.com Secondary published
CVSS 3.1 5.3 MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L NVD Primary

Affected software and releases

Maven packages

Affected and fixed versions, from OSV.dev
PackageIntroducedFixedLast affected
org.http4s:http4s-core_2.13 0.1.0 0.21.34 unbounded
org.http4s:http4s-core_2.13 0.22.0 0.22.15 unbounded
org.http4s:http4s-core_2.13 0.23.0 0.23.17 unbounded
org.http4s:http4s-core_2.13 1.0.0-M1 1.0.0-M38 unbounded
org.http4s:http4s-core_2.10 0.1.0 none 0.9.3
org.http4s:http4s-core_2.11 0.1.0 none 0.21.0-M1
org.http4s:http4s-core_2.12 0.1.0 0.21.34 unbounded
org.http4s:http4s-core_2.12 0.22.0 0.22.15 unbounded
org.http4s:http4s-core_2.12 0.23.0 0.23.17 unbounded
org.http4s:http4s-core 1.0.0-M1 none 1.0.0-M30

Products and versions

6 products, 50 version entries
SourceVendorProductSchemeAffected versions
osv org.http4s http4s-core generic ≥ 1.0.0 and ≤ 1.0.0
osv org.http4s http4s-core_2.10 generic ≥ 0.1.0 and ≤ 0.9.3
osv org.http4s http4s-core_2.11 generic ≥ 0.1.0 and ≤ 0.21.0
osv org.http4s http4s-core_2.12 generic ≥ 0.1.0 and < 0.21.34 · ≥ 0.22.0 and < 0.22.15 · ≥ 0.23.0 and < 0.23.17
osv org.http4s http4s-core_2.13 generic ≥ 0.1.0 and < 0.21.34 · ≥ 0.22.0 and < 0.22.15 · ≥ 0.23.0 and < 0.23.17 · ≥ 1.0.0 and < 1.0.0
nvd typelevel http4s generic ≥ 0.1.0 and < 0.21.34 · ≥ 0.22.0 and < 0.22.15 · ≥ 0.23.0 and < 0.23.17 · 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 · 1.0.0:milestone16 · 1.0.0:milestone17 · 1.0.0:milestone18 · 1.0.0:milestone19 · 1.0.0:milestone2 · 1.0.0:milestone20 · 1.0.0:milestone21 · 1.0.0:milestone22 · 1.0.0:milestone23 · 1.0.0:milestone24 · 1.0.0:milestone25 · 1.0.0:milestone26 · 1.0.0:milestone27 · 1.0.0:milestone28 · 1.0.0:milestone29 · 1.0.0:milestone3 · 1.0.0:milestone30 · 1.0.0:milestone31 · 1.0.0:milestone32 · 1.0.0:milestone33 · 1.0.0:milestone34 · 1.0.0:milestone35 · 1.0.0:milestone36 · 1.0.0:milestone37 · 1.0.0:milestone4 · 1.0.0:milestone5 · 1.0.0:milestone6 · 1.0.0:milestone7 · 1.0.0:milestone8 · 1.0.0:milestone9

References

URLTags
https://github.com/http4s/http4s/security/advisories/GHSA-54w6-vxfh-fw7f advisory
https://github.com/http4s/http4s PACKAGE

Timeline

Published2023-01-04By the CVE Program.
NVD record modified2026-06-17NVD's own last-modified date for this record.