GHSA-P6Q4-FGR8-VX4P

Vulnerability from github – Published: 2026-03-24 22:06 – Updated: 2026-07-06 13:07
VLAI
Summary
Scriban has a Stack Overflow via Nested Array Initializers That Bypass the ExpressionDepthLimit Fix
Details

Summary

StackOverflowException via nested array initializers bypasses ExpressionDepthLimit fix (GHSA-wgh7-7m3c-fx25)

Details

The recent fix for GHSA-wgh7-7m3c-fx25 (uncontrolled recursion in parser) added ExpressionDepthLimit defaulting to 250. However, deeply nested array initializers ([[[[...) recurse through ParseArrayInitializer → ParseExpression → ParseArrayInitializer, which is a different recursion path not covered by the expression depth counter.

This causes a StackOverflowException on current main (commit b5ac4bf - "Add limits for default safety").

PoC

using Scriban;

// ExpressionDepthLimit (default 250) does NOT prevent this crash
string nested = "{{ " + new string('[', 5000) + "1" + new string(']', 5000) + " }}";
Template.Parse(nested); // StackOverflowException - process terminates

Impact

Same as GHSA-wgh7-7m3c-fx25: High severity. StackOverflowException cannot be caught with try/catch in .NET - the process terminates immediately. Any application calling Template.Parse with untrusted input is vulnerable, even with the new default ExpressionDepthLimit enabled.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Show details on source website
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{
  "affected": [
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "Scriban"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "Scriban.Signed"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-674"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-24T22:06:24Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\nStackOverflowException via nested array initializers bypasses ExpressionDepthLimit fix (GHSA-wgh7-7m3c-fx25)\n\n### Details\nThe recent fix for GHSA-wgh7-7m3c-fx25 (uncontrolled recursion in parser) added `ExpressionDepthLimit` defaulting to 250. However, deeply nested **array initializers** (`[[[[...`) recurse through `ParseArrayInitializer` \u2192 `ParseExpression` \u2192 `ParseArrayInitializer`, which is a **different recursion path** not covered by the expression depth counter.\n\nThis causes a `StackOverflowException` on current main (commit b5ac4bf - \"Add limits for default safety\").\n\n### PoC\n```\nusing Scriban;\n\n// ExpressionDepthLimit (default 250) does NOT prevent this crash\nstring nested = \"{{ \" + new string(\u0027[\u0027, 5000) + \"1\" + new string(\u0027]\u0027, 5000) + \" }}\";\nTemplate.Parse(nested); // StackOverflowException - process terminates\n```\n\n### Impact\nSame as GHSA-wgh7-7m3c-fx25: High severity. StackOverflowException cannot be caught with try/catch in .NET - the process terminates immediately. Any application calling Template.Parse with untrusted input is vulnerable, even with the new default ExpressionDepthLimit enabled.",
  "id": "GHSA-p6q4-fgr8-vx4p",
  "modified": "2026-07-06T13:07:26Z",
  "published": "2026-03-24T22:06:24Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/scriban/scriban/security/advisories/GHSA-p6q4-fgr8-vx4p"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-wgh7-7m3c-fx25"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/scriban/scriban"
    }
  ],
  "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": "Scriban has a Stack Overflow via Nested Array Initializers That Bypass the ExpressionDepthLimit Fix"
}



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