CVE-2026-69206 Http4s: DigestAuth allows replay of captured requests
Attackers can replay captured HTTP requests to execute authenticated actions as the victim due to flawed nonce-count tracking in Http4s DigestAuth.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-69206?
CVE-2026-69206 is a medium-severity vulnerability in http4s, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-294
Which versions are affected by CVE-2026-69206?
10 open source packages ship an affected version, including org.http4s:http4s-ember-core_2.13, org.http4s:http4s-ember-core_2.12 and org.http4s:http4s-ember-core_3.
| Package | Affected | Fixed in |
|---|---|---|
org.http4s:http4s-ember-core_2.13 Maven | All versions | 0.23.35 |
org.http4s:http4s-ember-core_2.13 Maven | All versions | 0.23.35 |
org.http4s:http4s-ember-core_2.13 Maven | From 1.0.0-M1 | 1.0.0-M47 |
org.http4s:http4s-ember-core_2.13 Maven | From 1.0.0-M1 | 1.0.0-M47 |
org.http4s:http4s-ember-core_2.12 Maven | All versions | 0.23.35 |
org.http4s:http4s-ember-core_2.12 Maven | All versions | 0.23.35 |
4 more packages
org.http4s:http4s-ember-core_3 Maven | All versions | 0.23.35 |
org.http4s:http4s-ember-core_3 Maven | All versions | 0.23.35 |
org.http4s:http4s-ember-core_3 Maven | From 1.0.0-M1 | 1.0.0-M47 |
org.http4s:http4s-ember-core_3 Maven | From 1.0.0-M1 | 1.0.0-M47 |
How do I fix CVE-2026-69206?
Upgrade org.http4s:http4s-ember-core_2.13 to a fixed version for your release line: 0.23.35 or 1.0.0-M47.
Is CVE-2026-69206 being exploited?
There is no known exploitation of CVE-2026-69206 in the wild and no public exploit code.
Sources
Also known as GHSA-9xww-74xv-gjfp.