CVE-2026-40303

HIGH

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

Title source: cna
STIX 2.1

Description

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.

Scores

CVSS v3 7.5
EPSS 0.0003
EPSS Percentile 8.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-400 CWE-789
Status published
Products (2)
netfoundry/zrok < 2.0.1
openziti/zrok < 2.0.1
Published Apr 17, 2026
Tracked Since Apr 18, 2026