{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-67194", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-07-28T16:06:49.774Z", "datePublished": "2026-07-29T16:39:09.617Z", "dateUpdated": "2026-08-14T16:50:49.429Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-08-14T16:50:49.429Z"}, "title": "Courier IMAP < 6.0.1 Mail Server < 2.0.2 Stack Overflow DoS via Nested SEARCH Queries", "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."}], "tags": ["x_open-source"], "datePublic": "2026-07-29T00:00:00.000Z", "problemTypes": [{"descriptions": [{"lang": "en", "cweId": "CWE-674", "description": "Uncontrolled Recursion", "type": "CWE"}]}], "affected": [{"defaultStatus": "affected", "vendor": "svarshavchik", "product": "Courier IMAP", "packageURL": "pkg:github/svarshavchik/courier", "repo": "https://github.com/svarshavchik/courier", "versions": [{"status": "affected", "version": "0", "versionType": "semver", "lessThan": "6.0.1"}]}, {"defaultStatus": "affected", "vendor": "svarshavchik", "product": "Courier Mail Server", "packageURL": "pkg:github/svarshavchik/courier", "repo": "https://github.com/svarshavchik/courier", "versions": [{"status": "affected", "version": "0", "versionType": "semver", "lessThan": "2.0.2"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:courier-mta:courier_mail_server:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.0.2"}]}]}], "metrics": [{"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV4_0": {"attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subIntegrityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subAvailabilityImpact": "NONE", "exploitMaturity": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "version": "4.0", "baseSeverity": "HIGH", "baseScore": 7.1, "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"}}, {"format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}], "cvssV3_1": {"attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH", "version": "3.1", "baseSeverity": "MEDIUM", "baseScore": 6.5, "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}}], "references": [{"url": "https://github.com/svarshavchik/courier/releases/tag/courier-imap%2F6.0.1%2F20260627214444", "name": "Courier IMAP Release Notes", "tags": ["release-notes"]}, {"url": "https://github.com/svarshavchik/courier/releases/tag/courier%2F2.0.2%2F20260627214309", "name": "Courier Mail Server Release Notes", "tags": ["release-notes"]}, {"url": "https://github.com/svarshavchik/courier-libs/commit/b5b5581aabea3efadf5e2944947ff0214aa3533e", "name": "Patch Commit", "tags": ["patch"]}, {"url": "https://packages.debian.org/sid/courier-imap", "name": "Debian Package", "tags": ["product"]}, {"url": "https://www.vulncheck.com/advisories/courier-imap-mail-server-stack-overflow-dos-via-nested-search-queries", "tags": ["third-party-advisory"]}], "credits": [{"lang": "en", "value": "Tristan Madani", "type": "finder"}], "source": {"discovery": "UNKNOWN"}, "x_generator": {"engine": "vulncheck"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-07-29T18:07:00.293768Z", "id": "CVE-2026-67194", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-29T18:07:09.182Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-67194", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-29T18:07:00.293768Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-29T18:07:04.575Z"}}], "cna": {"tags": ["x_open-source"], "title": "Courier IMAP < 6.0.1 Mail Server < 2.0.2 Stack Overflow DoS via Nested SEARCH Queries", "source": {"discovery": "UNKNOWN"}, "credits": [{"lang": "en", "type": "finder", "value": "Tristan Madani"}], "metrics": [{"format": "CVSS", "cvssV4_0": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 7.1, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}, {"format": "CVSS", "cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"repo": "https://github.com/svarshavchik/courier", "vendor": "svarshavchik", "product": "Courier IMAP", "versions": [{"status": "affected", "version": "0", "lessThan": "6.0.1", "versionType": "semver"}], "packageURL": "pkg:github/svarshavchik/courier", "defaultStatus": "affected"}, {"repo": "https://github.com/svarshavchik/courier", "vendor": "svarshavchik", "product": "Courier Mail Server", "versions": [{"status": "affected", "version": "0", "lessThan": "2.0.2", "versionType": "semver"}], "packageURL": "pkg:github/svarshavchik/courier", "defaultStatus": "affected"}], "datePublic": "2026-07-29T00:00:00.000Z", "references": [{"url": "https://github.com/svarshavchik/courier/releases/tag/courier-imap%2F6.0.1%2F20260627214444", "name": "Courier IMAP Release Notes", "tags": ["release-notes"]}, {"url": "https://github.com/svarshavchik/courier/releases/tag/courier%2F2.0.2%2F20260627214309", "name": "Courier Mail Server Release Notes", "tags": ["release-notes"]}, {"url": "https://github.com/svarshavchik/courier-libs/commit/b5b5581aabea3efadf5e2944947ff0214aa3533e", "name": "Patch Commit", "tags": ["patch"]}, {"url": "https://packages.debian.org/sid/courier-imap", "name": "Debian Package", "tags": ["product"]}, {"url": "https://www.vulncheck.com/advisories/courier-imap-mail-server-stack-overflow-dos-via-nested-search-queries", "tags": ["third-party-advisory"]}], "x_generator": {"engine": "vulncheck"}, "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."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-674", "description": "Uncontrolled Recursion"}]}], "providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-07-29T16:39:09.617Z"}}}, "cveMetadata": {"cveId": "CVE-2026-67194", "state": "PUBLISHED", "dateUpdated": "2026-07-29T18:07:09.182Z", "dateReserved": "2026-07-28T16:06:49.774Z", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "datePublished": "2026-07-29T16:39:09.617Z", "assignerShortName": "VulnCheck"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"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"}]}], "source": "disclosure@vulncheck.com"}], "cveTags": [], "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."}], "id": "CVE-2026-67194", "lastModified": "2026-07-30T20:11:09.180", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "disclosure@vulncheck.com", "type": "Secondary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 7.1, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "disclosure@vulncheck.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-67194", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-07-29T18:07:00.293768Z", "version": "2.0.3"}}]}, "published": "2026-07-29T17:16:54.017", "references": [{"source": "disclosure@vulncheck.com", "url": "https://github.com/svarshavchik/courier-libs/commit/b5b5581aabea3efadf5e2944947ff0214aa3533e"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/svarshavchik/courier/releases/tag/courier%2F2.0.2%2F20260627214309"}, {"source": "disclosure@vulncheck.com", "url": "https://github.com/svarshavchik/courier/releases/tag/courier-imap%2F6.0.1%2F20260627214444"}, {"source": "disclosure@vulncheck.com", "url": "https://packages.debian.org/sid/courier-imap"}, {"source": "disclosure@vulncheck.com", "url": "https://www.vulncheck.com/advisories/courier-imap-mail-server-stack-overflow-dos-via-nested-search-queries"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-674"}], "source": "disclosure@vulncheck.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,6.0.1)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "original": {"product": "Courier IMAP", "source": "cna", "vendor": "svarshavchik"}, "product": "courier_imap", "vendor": "svarshavchik"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,2.0.2)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "original": {"product": "Courier Mail Server", "source": "cna", "vendor": "svarshavchik"}, "product": "courier_mail_server", "vendor": "svarshavchik"}], "created": "2026-07-30T14:01:52.773503+00:00", "updated": "2026-08-03T13:15:05.189497+00:00", "vendors": ["svarshavchik", "svarshavchik$PRODUCT$courier_imap", "svarshavchik$PRODUCT$courier_mail_server"]}