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CVE-2026-40303
Published:April 17, 2026
Updated:April 23, 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.
Affected Packages
https://github.com/openziti/zrok.git (GITHUB):
Affected version(s) >=v1.1.9 <v2.0.1
Fix Suggestion:
Update to version v2.0.1
github.com/openziti/zrok/v2 (GO):
Affected version(s) >=v2.0.0-rc4 <v2.0.1
Fix Suggestion:
Update to version v2.0.1
github.com/openziti/zrok (GO):
Affected version(s) >=v1.1.9 <v2.0.1
Fix Suggestion:
Update to version v2.0.1
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CVSS v4
Base Score:
8.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
HIGH
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Weakness Type (CWE)
Memory Allocation with Excessive Size Value
Uncontrolled Resource Consumption
EPSS
Base Score:
0.02