{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "source": "REFERENCES"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "b5b5581aabea3efadf5e2944947ff0214aa3533e"
            }
          ],
          "repo": "https://github.com/svarshavchik/courier-libs",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-674"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67194.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "fixed": "6.0.1"
          },
          {
            "fixed": "2.0.2"
          }
        ],
        "source": "AFFECTED_FIELD"
      },
      {
        "extracted_events": [
          {
            "fixed": "6.0.1"
          },
          {
            "fixed": "2.0.2"
          }
        ],
        "source": "DESCRIPTION"
      }
    ]
  },
  "details": "Courier IMAP before 6.0.1 and Courier Mail Server before 2.0.2 allow authenticated IMAP users to crash the imapd process via deeply nested parenthesized SEARCH queries. The SEARCH command parser (alloc_search_key in searchinfo.C) recursively descends on nested parenthesized groups through a mutual recursion chain with alloc_search_andlist() and alloc_search_notkey(), with no depth limit. Courier IMAP has no overall command line length limit, making exploitation trivial. A single IMAP command with ~2500 nested parentheses overflows the 8MB default stack, causing SIGSEGV.",
  "id": "CVE-2026-67194",
  "modified": "2026-08-01T03:33:10.276383850Z",
  "published": "2026-07-29T16:39:09.617Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://packages.debian.org/sid/courier-imap"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67194.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/svarshavchik/courier/releases/tag/courier%2F2.0.2%2F20260627214309"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/svarshavchik/courier/releases/tag/courier-imap%2F6.0.1%2F20260627214444"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-67194"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/courier-imap-mail-server-stack-overflow-dos-via-nested-search-queries"
    },
    {
      "type": "FIX",
      "url": "https://github.com/svarshavchik/courier-libs/commit/b5b5581aabea3efadf5e2944947ff0214aa3533e"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/svarshavchik/courier"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Courier IMAP \u003c 6.0.1 Mail Server \u003c 2.0.2 Stack Overflow DoS via Nested SEARCH Queries"
}