CVE intelligence and bounded remediation
CVE-2026-40303 — zrok is software for sharing web services, files, and network resources
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.
- Severity
- High
- CVSS
- 7.5 (3.1)
- Published
- 2026-04-17
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-400, CWE-789
Affected products
- netfoundry / zrok
Matched remediation archetype
Resource exhaustion and denial of service
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
Check exposure
- Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
- Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
- Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.
Remediate safely
- Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
- Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
- Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.
Authoritative sources
Complete CVE record and remediation plan
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