CVE-2026-69208: Http4s: DigestAuth nonce map grows unbounded

Description

Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, the DigestAuth server middleware removes fresh nonces and stops eviction at the first stale nonce because its stale-nonce comparison is inverted. On an application that protects at least one route with DigestAuth, an unauthenticated attacker can repeatedly trigger authentication challenges, causing the persistent nonce map to grow until the JVM exhausts heap memory. This issue is fixed in versions 0.23.35 and 1.0.0-M47.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack vector

Network

Complexity

Low

Privileges

None

User interaction

None

Confidentiality

None

Integrity

None

Availability

High

Scope

Unchanged

Exploitation

Is it being used?

Exploit prediction (EPSS)0.8% · higher than 55% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

HT

http4s · http4s

< 0.23.35; >= 1.0.0-M1, < 1.0.0-M47 · source: vendor