CVE-2026-40303 PUBLISHED

zrok allows unauthenticated DoS via unbounded memory allocation in striped session cookie parsing

Assigner: GitHub_M
Reserved: 10.04.2026 Published: 17.04.2026 Updated: 17.04.2026

zrok is software for sharing web services, files, and network resources. Prior to version 2.0.1, endpoints.GetSessionCookie parses an attacker-supplied cookie chunk count and calls make([]string, count) with no upper bound before any token validation occurs. The function is reached on every request to an OAuth-protected proxy share, allowing an unauthenticated remote attacker to trigger gigabyte-scale heap allocations per request, leading to process-level OOM termination or repeated goroutine panics. Both publicProxy and dynamicProxy are affected. Version 2.0.1 patches the issue.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 7.5

Product Status

Vendor openziti
Product zrok
Versions
  • Version < 2.0.1 is affected

References

Problem Types

  • CWE-400: Uncontrolled Resource Consumption CWE
  • CWE-789: Memory Allocation with Excessive Size Value CWE