CVE-2026-22045
Published: 15 January 2026
Summary
CVE-2026-22045 is a medium-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Traefik Traefik. Its CVSS base score is 5.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application Exhaustion Flood (T1499.003); ranked at the 5.2th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
Threat & Defense at a Glance
Threat & Defense Details
Likely Mitigating ControlsAI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
This control implements explicit throttling on session allocation, addressing the weakness of allocating resources without limits.
Plan testing exercises resource allocation limits and throttling during simulated failures, directly addressing weaknesses that allow unbounded resource use.
Contingency plan updates ensure recovery strategies address unbounded resource allocation, making it harder for attackers to exploit lack of throttling to cause prolonged outages.
Provides continuity when unbounded resource allocation at the primary site leads to exhaustion and downtime.
Alternate services allow operations to continue when primary allocation of resources lacks limits or throttling.
Explicit planning of security-related actions requires defining limits, windows, and resource allocations, making allocation without throttling far less likely.
Measures of performance include tracking allocation behavior and throttling effectiveness, reducing the window for resource exhaustion attacks.
Imposes an inactivity-based limit on network resource allocation, throttling the number of concurrently held connections.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Direct resource exhaustion DoS via unauthenticated TLS-ALPN connections targeting application-layer handling in a public-facing proxy.
NVD Description
Traefik is an HTTP reverse proxy and load balancer. Prior to 2.11.35 and 3.6.7, there is a potential vulnerability in Traefik ACME TLS certificates' automatic generation: the ACME TLS-ALPN fast path can allow unauthenticated clients to tie up go routines…
more
and file descriptors indefinitely when the ACME TLS challenge is enabled. A malicious client can open many connections, send a minimal ClientHello with acme-tls/1, then stop responding, leading to denial of service of the entry point. The vulnerability is fixed in 2.11.35 and 3.6.7.
Deeper analysisAI
CVE-2026-22045 is a denial-of-service vulnerability in Traefik, an open-source HTTP reverse proxy and load balancer. It affects versions prior to 2.11.35 and 3.6.7, specifically in the ACME TLS certificates' automatic generation feature when the ACME TLS challenge is enabled. The issue stems from the ACME TLS-ALPN fast path, which allows unauthenticated clients to indefinitely tie up Go routines and file descriptors. This is classified under CWE-770 (Allocation of Resources Without Limits or Throttling) with a CVSS v3.1 base score of 5.9 (AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H).
Any unauthenticated attacker with network access to the Traefik entry point can exploit this vulnerability. The attack involves opening numerous TCP connections, sending a minimal TLS ClientHello containing the acme-tls/1 ALPN identifier, and then ceasing to respond. This exhausts server resources, leading to denial of service on the affected entry point by preventing legitimate traffic from being processed.
Traefik addresses the vulnerability in releases 2.11.35 and 3.6.7, as detailed in the project's security advisory (GHSA-cwjm-3f7h-9hwq) and corresponding release notes. The fixing commit (e9f3089e9045812bcf1b410a9d40568917b26c3d) resolves the resource exhaustion in the ACME TLS-ALPN handling. Security practitioners should upgrade to these patched versions and review configurations to ensure ACME TLS challenges are only enabled where necessary.
Details
- CWE(s)