CVE-2026-69206

CVE-2026-69206 is a medium-severity security vulnerability in org.http4s:http4s-ember-core_2.12 (maven), affecting versions <= 0.23.34. It is fixed in 0.23.35, 1.0.0-M47.

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Runtime intelligence, not another scanner.

Summary

Http4s: DigestAuth allows replay of captured requests

The DigestAuth replay defence stores lastNc + 1 rather than the nonce-count (nc) value it just accepted. When a legitimate client sends non-contiguous nc values (parallel or retried requests, as browsers do), the server's counter lags behind the highest nc seen, and a captured Authorization header can be replayed multiple times.

Preconditions

  • Application uses DigestAuth.
  • Attacker can passively observe at least one legitimate digest request.
  • Legitimate client emits an nc more than one greater than the last, for instance from a parallel or retried request.

Workarounds

  • Deploy over TLS so requests cannot be captured.

Impact

A passive observer can turn one captured Digest-authenticated request into several replayed authenticated (state-changing) requests, defeating the core
replay protection Digest provides over Basic.

CVE-2026-69206 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.23.35, 1.0.0-M47); upgrading removes the vulnerable code path.

Affected versions

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)

Security releases

org.http4s:http4s-ember-core_2.12 → 0.23.35 (maven) org.http4s:http4s-ember-core_2.13 → 0.23.35 (maven) org.http4s:http4s-ember-core_3 → 0.23.35 (maven) org.http4s:http4s-ember-core_2.13 → 1.0.0-M47 (maven) org.http4s:http4s-ember-core_3 → 1.0.0-M47 (maven)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Upgrade the following packages to resolve this vulnerability:

org.http4s:http4s-ember-core_2.12 to 0.23.35 or later; org.http4s:http4s-ember-core_2.13 to 0.23.35 or later; org.http4s:http4s-ember-core_3 to 0.23.35 or later; org.http4s:http4s-ember-core_2.13 to 1.0.0-M47 or later; org.http4s:http4s-ember-core_3 to 1.0.0-M47 or later

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

  1. What is CVE-2026-69206? CVE-2026-69206 is a medium-severity security vulnerability in org.http4s:http4s-ember-core_2.12 (maven), affecting versions <= 0.23.34. It is fixed in 0.23.35, 1.0.0-M47.
  2. How severe is CVE-2026-69206? CVE-2026-69206 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
  3. Which packages are affected by CVE-2026-69206?
    • org.http4s:http4s-ember-core_2.12 (maven) (versions <= 0.23.34)
    • org.http4s:http4s-ember-core_2.13 (maven) (versions <= 0.23.34)
    • org.http4s:http4s-ember-core_3 (maven) (versions <= 0.23.34)
  4. Is there a fix for CVE-2026-69206? Yes. CVE-2026-69206 is fixed in 0.23.35, 1.0.0-M47. Upgrade to this version or later.
  5. Is CVE-2026-69206 exploitable, and should I be worried? Whether CVE-2026-69206 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
  6. What actually determines whether CVE-2026-69206 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
  7. How do I fix CVE-2026-69206?
    • Upgrade org.http4s:http4s-ember-core_2.12 to 0.23.35 or later
    • Upgrade org.http4s:http4s-ember-core_2.13 to 0.23.35 or later
    • Upgrade org.http4s:http4s-ember-core_3 to 0.23.35 or later
    • Upgrade org.http4s:http4s-ember-core_2.13 to 1.0.0-M47 or later
    • Upgrade org.http4s:http4s-ember-core_3 to 1.0.0-M47 or later

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