CVE-2026-40303CWE-400CWE-789

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

High · published April 17, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
47.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00590 · 47.5th percentile
Weaknesses
CWE-400 · Uncontrolled Resource Consumption; CWE-789 · Memory Allocation with Excessive Size Value
Published
2026-04-17T21:01Z
EPSS history
Timeline
  • 17 APR 21:01Z
    zrok allows unauthenticated DoS via unbounded memory allocation in striped session cookie parsing
    cvelistv5