Vulnerability-Lookup

ubuntu-cve-2026-67194

Vulnerability from osv_ubuntu

Published

2026-07-30 00:00

Modified

2026-07-31 12:09

Summary

Details

(Courier IMAP before 6.0.1 and Courier Mail Server before 2.0.2 allow a ...)

Severity

6.5 (Medium)


                    
                      CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

7.1 (High)


                    
                      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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-67194	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-67194	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "courier-base",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "courier-faxmail",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "courier-imap",
            "binary_version": "4.10.0-20120615-1ubuntu7"
          },
          {
            "binary_name": "courier-imap-ssl",
            "binary_version": "4.10.0-20120615-1ubuntu7"
          },
          {
            "binary_name": "courier-ldap",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "courier-maildrop",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "courier-mlm",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "courier-mta",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "courier-mta-ssl",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "courier-pcp",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "courier-pop",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "courier-pop-ssl",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "courier-ssl",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "courier-webadmin",
            "binary_version": "0.68.2-1ubuntu7"
          },
          {
            "binary_name": "sqwebmail",
            "binary_version": "0.68.2-1ubuntu7"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "courier",
        "purl": "pkg:deb/ubuntu/courier@0.68.2-1ubuntu7?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.68.2-1ubuntu5",
        "0.68.2-1ubuntu6",
        "0.68.2-1ubuntu7"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "courier-base",
            "binary_version": "0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-faxmail",
            "binary_version": "0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-imap",
            "binary_version": "4.18.1+0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-imap-ssl",
            "binary_version": "4.18.1+0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-ldap",
            "binary_version": "0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-maildrop",
            "binary_version": "2.9.1+0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-mlm",
            "binary_version": "0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-mta",
            "binary_version": "0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-mta-ssl",
            "binary_version": "0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-pcp",
            "binary_version": "0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-pop",
            "binary_version": "0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-pop-ssl",
            "binary_version": "0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-ssl",
            "binary_version": "0.78.0-2ubuntu2"
          },
          {
            "binary_name": "courier-webadmin",
            "binary_version": "0.78.0-2ubuntu2"
          },
          {
            "binary_name": "sqwebmail",
            "binary_version": "5.9.0+0.78.0-2ubuntu2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "courier",
        "purl": "pkg:deb/ubuntu/courier@0.78.0-2ubuntu2?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.78.0-2",
        "0.78.0-2ubuntu1",
        "0.78.0-2ubuntu2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "courier-base",
            "binary_version": "1.0.6-1build2"
          },
          {
            "binary_name": "courier-faxmail",
            "binary_version": "1.0.6-1build2"
          },
          {
            "binary_name": "courier-imap",
            "binary_version": "5.0.6+1.0.6-1build2"
          },
          {
            "binary_name": "courier-ldap",
            "binary_version": "1.0.6-1build2"
          },
          {
            "binary_name": "courier-mlm",
            "binary_version": "1.0.6-1build2"
          },
          {
            "binary_name": "courier-mta",
            "binary_version": "1.0.6-1build2"
          },
          {
            "binary_name": "courier-pcp",
            "binary_version": "1.0.6-1build2"
          },
          {
            "binary_name": "courier-pop",
            "binary_version": "1.0.6-1build2"
          },
          {
            "binary_name": "courier-webadmin",
            "binary_version": "1.0.6-1build2"
          },
          {
            "binary_name": "sqwebmail",
            "binary_version": "6.0.0+1.0.6-1build2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "courier",
        "purl": "pkg:deb/ubuntu/courier@1.0.6-1build2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0.6-1build1",
        "1.0.6-1build2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "courier-base",
            "binary_version": "1.0.16-3build3"
          },
          {
            "binary_name": "courier-faxmail",
            "binary_version": "1.0.16-3build3"
          },
          {
            "binary_name": "courier-imap",
            "binary_version": "5.0.13+1.0.16-3build3"
          },
          {
            "binary_name": "courier-ldap",
            "binary_version": "1.0.16-3build3"
          },
          {
            "binary_name": "courier-mlm",
            "binary_version": "1.0.16-3build3"
          },
          {
            "binary_name": "courier-mta",
            "binary_version": "1.0.16-3build3"
          },
          {
            "binary_name": "courier-pcp",
            "binary_version": "1.0.16-3build3"
          },
          {
            "binary_name": "courier-pop",
            "binary_version": "1.0.16-3build3"
          },
          {
            "binary_name": "courier-webadmin",
            "binary_version": "1.0.16-3build3"
          },
          {
            "binary_name": "sqwebmail",
            "binary_version": "6.0.5+1.0.16-3build3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "courier",
        "purl": "pkg:deb/ubuntu/courier@1.0.16-3build3?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0.16-3build1",
        "1.0.16-3build2",
        "1.0.16-3build3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "courier-base",
            "binary_version": "1.5.1-2"
          },
          {
            "binary_name": "courier-faxmail",
            "binary_version": "1.5.1-2"
          },
          {
            "binary_name": "courier-imap",
            "binary_version": "5.3.1+1.5.1-2"
          },
          {
            "binary_name": "courier-ldap",
            "binary_version": "1.5.1-2"
          },
          {
            "binary_name": "courier-mlm",
            "binary_version": "1.5.1-2"
          },
          {
            "binary_name": "courier-mta",
            "binary_version": "1.5.1-2"
          },
          {
            "binary_name": "courier-pcp",
            "binary_version": "1.5.1-2"
          },
          {
            "binary_name": "courier-pop",
            "binary_version": "1.5.1-2"
          },
          {
            "binary_name": "courier-webadmin",
            "binary_version": "1.5.1-2"
          },
          {
            "binary_name": "sqwebmail",
            "binary_version": "6.3.1+1.5.1-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "courier",
        "purl": "pkg:deb/ubuntu/courier@1.5.1-2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.4.1-3",
        "1.4.1-10",
        "1.5.1-2"
      ]
    }
  ],
  "aliases": [],
  "details": "(Courier IMAP before 6.0.1 and Courier Mail Server before 2.0.2 allow a ...)",
  "id": "UBUNTU-CVE-2026-67194",
  "modified": "2026-07-31T12:09:41Z",
  "published": "2026-07-30T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-67194"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-67194"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "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"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-67194"
  ]
}

CVE-2026-67194 (GCVE-0-2026-67194)

Vulnerability from cvelistv5 – Published: 2026-07-29 16:39 – Updated: 2026-07-29 18:07 X_Open Source

Title

Courier IMAP < 6.0.1 Mail Server < 2.0.2 Stack Overflow DoS via Nested SEARCH Queries

Summary

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.

Severity

7.1 (High)


                        
                          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

6.5 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-674 - Uncontrolled Recursion

Assigner

VulnCheck

References

5 references

URL	Tags
https://github.com/svarshavchik/courier/releases/…	release-notes
https://github.com/svarshavchik/courier/releases/…	release-notes
https://github.com/svarshavchik/courier-libs/comm…	patch
https://packages.debian.org/sid/courier-imap	product
https://www.vulncheck.com/advisories/courier-imap…	third-party-advisory

Impacted products

2 products

Vendor	Product	Version
svarshavchik	Courier IMAP	Affected: 0 , < 6.0.1 (semver)
svarshavchik	Courier Mail Server	Affected: 0 , < 2.0.2 (semver)

Date Public

2026-07-29 00:00

Credits

Tristan Madani

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-67194",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-29T18:07:00.293768Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-29T18:07:09.182Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "affected",
          "packageURL": "pkg:github/svarshavchik/courier",
          "product": "Courier IMAP",
          "repo": "https://github.com/svarshavchik/courier",
          "vendor": "svarshavchik",
          "versions": [
            {
              "lessThan": "6.0.1",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "packageURL": "pkg:github/svarshavchik/courier",
          "product": "Courier Mail Server",
          "repo": "https://github.com/svarshavchik/courier",
          "vendor": "svarshavchik",
          "versions": [
            {
              "lessThan": "2.0.2",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Tristan Madani"
        }
      ],
      "datePublic": "2026-07-29T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "LOW",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        },
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 6.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-674",
              "description": "Uncontrolled Recursion",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-29T16:39:09.617Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "Courier IMAP Release Notes",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/svarshavchik/courier/releases/tag/courier-imap%2F6.0.1%2F20260627214444"
        },
        {
          "name": "Courier Mail Server Release Notes",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/svarshavchik/courier/releases/tag/courier%2F2.0.2%2F20260627214309"
        },
        {
          "name": "Patch Commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/svarshavchik/courier-libs/commit/b5b5581aabea3efadf5e2944947ff0214aa3533e"
        },
        {
          "name": "Debian Package",
          "tags": [
            "product"
          ],
          "url": "https://packages.debian.org/sid/courier-imap"
        },
        {
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/courier-imap-mail-server-stack-overflow-dos-via-nested-search-queries"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "tags": [
        "x_open-source"
      ],
      "title": "Courier IMAP \u003c 6.0.1 Mail Server \u003c 2.0.2 Stack Overflow DoS via Nested SEARCH Queries",
      "x_generator": {
        "engine": "vulncheck"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-67194",
    "datePublished": "2026-07-29T16:39:09.617Z",
    "dateReserved": "2026-07-28T16:06:49.774Z",
    "dateUpdated": "2026-07-29T18:07:09.182Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

ubuntu-cve-2026-67194

Vulnerability from osv_ubuntu

CVE-2026-67194 (GCVE-0-2026-67194)

Tags

Sightings

Nomenclature