GHSA-CPF9-PH2J-CCR9

Vulnerability from github – Published: 2026-04-16 21:09 – Updated: 2026-04-16 21:09
VLAI?
Summary
zrok: Unauthenticated DoS via unbounded memory allocation in striped session cookie parsing
Details

Summary 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.

  • Attack Vector: Network — exploitable via a single HTTP request with a crafted Cookie header.
  • Attack Complexity: Low — no preconditions or chaining required; the attacker only needs to know the cookie name (publicly derivable from any OAuth redirect).
  • Privileges Required: None — reached before JWT validation or any authentication check.
  • User Interaction: None.
  • Scope: Unchanged — impact is confined to the affected proxy process.
  • Confidentiality Impact: None.
  • Integrity Impact: None.

Availability Impact: High — sustained or concurrent requests cause OOM process termination, taking down the proxy for all users of all shares it serves.

Affected Components - endpoints/oauthCookies.go — GetSessionCookie (line 81) - endpoints/publicProxy/authOAuth.go — handleOAuth (line 50) — call site, pre-auth - endpoints/dynamicProxy/cookies.go — getSessionCookie (line 29) — call site

Severity ?
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/openziti/zrok"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "1.1.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/openziti/zrok/v2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40303"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400",
      "CWE-789"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-16T21:09:08Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "**Summary**\nendpoints.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.\n\n- Attack Vector: Network \u2014 exploitable via a single HTTP request with a crafted Cookie header.\n- Attack Complexity: Low \u2014 no preconditions or chaining required; the attacker only needs to know the cookie name (publicly derivable from any OAuth redirect).\n- Privileges Required: None \u2014 reached before JWT validation or any authentication check.\n- User Interaction: None.\n- Scope: Unchanged \u2014 impact is confined to the affected proxy process.\n- Confidentiality Impact: None.\n- Integrity Impact: None.\n\nAvailability Impact: High \u2014 sustained or concurrent requests cause OOM process termination, taking down the proxy for all users of all shares it serves.\n\n**Affected Components**\n- endpoints/oauthCookies.go \u2014 GetSessionCookie (line 81)\n- endpoints/publicProxy/authOAuth.go \u2014 handleOAuth (line 50) \u2014 call site, pre-auth\n- endpoints/dynamicProxy/cookies.go \u2014 getSessionCookie (line 29) \u2014 call site",
  "id": "GHSA-cpf9-ph2j-ccr9",
  "modified": "2026-04-16T21:09:08Z",
  "published": "2026-04-16T21:09:08Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/openziti/zrok/security/advisories/GHSA-cpf9-ph2j-ccr9"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/openziti/zrok"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "zrok: Unauthenticated DoS via unbounded memory allocation in striped session cookie parsing"
}


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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.