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Vulnerabilities

Vulnerability · CVE-2026-40303

zrok is software for sharing web services, files, and network resources.

Published Apr 17, 2026 · catalog updated Jun 17, 2026 · zrok is software for

Check if you run it

No confirmed exploitation is on record for CVE-2026-40303. EPSS is 0.59%. Act only if a listed version of zrok is software for is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (zrok is software for).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.59%
Remediation
Advisory link
Affected products
cpe netfoundry/zrok

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe netfoundry/zrokversion unspecified

How to fix CVE-2026-40303

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-40303. EPSS is 0.59%. Act only if a listed version of zrok is software for is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-400: Uncontrolled Resource Consumption; CWE-789. EPSS 0.59%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 17, 2026 · NIST NVD

    Detected

    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-s

  2. Jun 17, 2026 · NIST NVD

    Updated

    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-s

Sources

  • CVE.orgVulnerability recordCVE-2026-40303

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-40303

    30-day exploitation probability 0.6%

    first.org
  • NIST NVDVulnerability recordCVE-2026-40303

    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 reach

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.