CVE-2026-34148

Fedify affected by resource exhaustion caused by unbounded redirect following during remote key/document resolution

This is an unauthenticated denial-of-service / request amplification issue. Any Fedify-based server that verifies remote keys or loads remote ActivityPub documents can be forced to spend CPU time, worker time, connection slots, and outbound bandwidth following attacker-controlled redirects. A single inbound request can trigger a large number of outbound requests, and the attack can be repeated across requests because failed lookups are not durably negatively cached.

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2026-34148 has a CVSS score of 7.5 (High). 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 (1.9.6, 2.0.8, 2.1.1, 1.10.5); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2026-34148? CVE-2026-34148 is a high-severity uncontrolled resource consumption vulnerability in @fedify/fedify (npm), affecting versions < 1.9.6. It is fixed in 1.9.6, 2.0.8, 2.1.1, 1.10.5. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
2. How severe is CVE-2026-34148? CVE-2026-34148 has a CVSS score of 7.5 (High). 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-2026-34148?
   • @fedify/fedify (npm) (versions < 1.9.6)
   • @fedify/vocab-runtime (npm) (versions < 2.0.8)
4. Is there a fix for CVE-2026-34148? Yes. CVE-2026-34148 is fixed in 1.9.6, 2.0.8, 2.1.1, 1.10.5. Upgrade to this version or later.
5. Is CVE-2026-34148 exploitable, and should I be worried? Whether CVE-2026-34148 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-2026-34148 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-2026-34148?
   • Upgrade @fedify/fedify to 1.9.6 or later
   • Upgrade @fedify/vocab-runtime to 2.0.8 or later
   • Upgrade @fedify/vocab-runtime to 2.1.1 or later
   • Upgrade @fedify/fedify to 1.10.5 or later
   • Upgrade @fedify/fedify to 2.0.8 or later
   • Upgrade @fedify/fedify to 2.1.1 or later