CVE-2026-40303
HIGHzrok allows unauthenticated DoS via unbounded memory allocation in striped session cookie parsing
Title source: cnaDescription
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.
References (2)
Core 2
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/openziti/zrok/security/advisories/GHSA-cpf9-ph2j-ccr9
X_Refsource_Misc x_refsource_misc
https://github.com/openziti/zrok/releases/tag/v2.0.1
Scores
CVSS v3
7.5
EPSS
0.0045
EPSS Percentile
35.7%
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 (4)
netfoundry/zrok
< 2.0.1
openziti/zrok
0Go
openziti/zrok
0 - 2.0.1Go
openziti/zrok
< 2.0.1
Published
Apr 17, 2026
Tracked Since
Apr 18, 2026