---
id: CVE-2026-69206
title: Http4s is a Scala interface for HTTP services
summary: >-
  Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47,
  DigestAuth replay protection records lastNc plus one instead of the highest
  nonce-count value it has accepted. When a legitimate client sends
  noncontiguous nc…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-294
vendor: http4s
product: http4s
affected:
  - http4s < 0.23.35
  - 'http4s >= 1.0.0-M1, < 1.0.0-M47'
patched:
  - 'org.http4s:http4s-ember-core_2.12 0.23.35'
  - 'org.http4s:http4s-ember-core_2.13 0.23.35'
  - 'org.http4s:http4s-ember-core_3 0.23.35'
  - 'org.http4s:http4s-ember-core_2.13 1.0.0-M47'
  - 'org.http4s:http4s-ember-core_3 1.0.0-M47'
published: '2026-09-15'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T20:39:16.610'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-69206'
references:
  - url: >-
      https://github.com/http4s/http4s/commit/7f065101c45f3d86bc105e8fc6323c2c4a11471f
    label: security-advisories@github.com
  - url: 'https://github.com/http4s/http4s/releases/tag/v0.23.35'
    label: security-advisories@github.com
  - url: 'https://github.com/http4s/http4s/releases/tag/v1.0.0-M47'
    label: security-advisories@github.com
  - url: 'https://github.com/http4s/http4s/security/advisories/GHSA-9xww-74xv-gjfp'
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-9xww-74xv-gjfp'
tags:
  - nvd
  - cve.org
  - ghsa
  - maven
aliases:
  - GHSA-9xww-74xv-gjfp
ecosystem: maven
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-16T17:44:48.301455Z'
ingestedAt: '2026-09-15T19:42:58.817Z'
epss: 0.00326
epssPercentile: 0.25924
---

## Overview

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, DigestAuth replay protection records lastNc plus one instead of the highest nonce-count value it has accepted. When a legitimate client sends noncontiguous nc values because of parallel or retried requests, the stored counter remains below the accepted maximum, allowing a passive observer to replay a captured Authorization header multiple times. Successful replays execute authenticated requests, including state-changing operations, as the captured user. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-69206)

Affected packages:

- `org.http4s:http4s-ember-core_2.12 <= 0.23.34`
- `org.http4s:http4s-ember-core_2.13 <= 0.23.34`
- `org.http4s:http4s-ember-core_3 <= 0.23.34`
- `org.http4s:http4s-ember-core_2.13 >= 1.0.0-M1, <= 1.0.0-M46`
- `org.http4s:http4s-ember-core_3 >= 1.0.0-M1, <= 1.0.0-M46`

Patched in:

- `org.http4s:http4s-ember-core_2.12 0.23.35`
- `org.http4s:http4s-ember-core_2.13 0.23.35`
- `org.http4s:http4s-ember-core_3 0.23.35`
- `org.http4s:http4s-ember-core_2.13 1.0.0-M47`
- `org.http4s:http4s-ember-core_3 1.0.0-M47`

Source: https://github.com/advisories/GHSA-9xww-74xv-gjfp