CVE-2026-40303: high-severity vulnerability in openziti zrok
zrok allows unauthenticated DoS via unbounded memory allocation in striped session cookie parsing
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.5%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
openziti · zrokRelated CVEs — openziti zrok
In the same product, most dangerous first.
CVE-2026-45568CRITICALzrok Python ProxyShare can be used as an SSRF proxy through absolute URL pathsEPSS 0.5%CVE-2026-45576HIGHzrok copy writes attacker-controlled WebDAV paths outside the destination rootEPSS 0.5%CVE-2026-42275HIGHzrok: WebDAV drive backend follows symlinks outside DriveRoot, enabling host filesystem read/writeEPSS 0.3%CVE-2026-40304MEDIUMzrok's broken ownership check in DELETE /api/v2/unaccess allows non-admin to delete global frontend recordsEPSS 0.3%CVE-2026-40302MEDIUMzrok has reflected XSS in GitHub OAuth callback via unsanitized refreshInterval error renderingEPSS 0.2%