Denial of Service Vulnerability in zrok Software by OpenZiti
CVE-2026-40303

7.5HIGH

Key Information:

Vendor

Openziti

Status
Zrok
Vendor
CVE Published:
17 April 2026

What is CVE-2026-40303?

The zrok software, utilized for sharing web services and files, contains a vulnerability in its GetSessionCookie function. This flaw occurs when the function processes attacker-controlled cookie chunk counts without enforcing an upper limit. As a result, an unauthenticated remote attacker can exploit this vulnerability on every request to an OAuth-protected proxy share, leading to significant heap allocations that can overwhelm the server. This can cause the system to experience out-of-memory (OOM) terminations or trigger multiple goroutine panics, impacting the availability and performance of the service. The issue has been resolved in version 2.0.1.

Affected Version(s)

zrok < 2.0.1

References

https://github.com/openziti/zrok/security/advisories/GHSA...
x_refsource_CONFIRM
https://github.com/openziti/zrok/releases/tag/v2.0.1
x_refsource_MISC

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.