CVE-2026-85597

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-85597", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-09-04T11:00:28.730Z", "datePublished": "2026-09-04T11:30:00.783Z", "dateUpdated": "2026-10-08T15:51:49.372Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-10-08T15:51:49.372Z"}, "datePublic": "2026-08-21T00:00:00.000Z", "title": "Traefik before v2.11.55 and v3.0.0 through v3.7.10 mTLS Bypass via TLS Option Conflict", "descriptions": [{"lang": "en", "value": "Traefik before v2.11.55 and v3.0.0 through v3.7.10 contain a TLS option conflict resolution vulnerability that allows unauthenticated attackers to bypass client-certificate authentication by creating conflicting TLS options on multi-host routers. Attackers can reach protected backends by exploiting shared TLS resolution across multiple hostnames in a single router rule, causing the strict mTLS requirement to fall back to default options for all hosts."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Incorrect Authorization", "cweId": "CWE-863", "type": "CWE"}]}], "affected": [{"vendor": "traefik", "product": "traefik", "defaultStatus": "unaffected", "packageURL": "pkg:golang/github.com/traefik/traefik/v2", "versions": [{"version": "0", "status": "affected", "versionType": "semver", "lessThan": "2.11.55"}, {"version": "2.11.55", "status": "unaffected", "versionType": "semver"}]}, {"vendor": "traefik", "product": "traefik", "defaultStatus": "unaffected", "packageURL": "pkg:golang/github.com/traefik/traefik/v3", "versions": [{"version": "3.0.0", "status": "affected", "versionType": "semver", "lessThanOrEqual": "3.7.10"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.11.55"}]}]}, {"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.0.0", "versionEndIncluding": "3.7.12"}]}]}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "userInteraction": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "baseScore": 8.2, "baseSeverity": "HIGH"}}], "references": [{"url": "https://github.com/traefik/traefik/security/advisories/GHSA-g55h-rg46-x9c5", "tags": ["vendor-advisory"], "name": "GitHub Security Advisory (GHSA-g55h-rg46-x9c5)"}, {"name": "VulnCheck Advisory: Traefik before v2.11.55 mTLS Bypass via TLS Option Conflict", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/traefik-before-2.11.55-mtls-bypass-via-tls-option-conflict"}], "credits": [{"lang": "en", "value": "james-yusuke", "type": "reporter"}], "x_generator": {"engine": "vulncheck-endgame"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-09-04T18:03:53.030722Z", "id": "CVE-2026-85597", "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": "2026-09-04T18:04:02.286Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-85597", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-09-04T18:03:53.030722Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-09-04T18:03:59.136Z"}}], "cna": {"title": "Traefik before v2.11.55 and v3.0.0 through v3.7.10 mTLS Bypass via TLS Option Conflict", "credits": [{"lang": "en", "type": "reporter", "value": "james-yusuke"}], "metrics": [{"format": "CVSS", "cvssV4_0": {"version": "4.0", "baseScore": 8.2, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "HIGH"}}], "affected": [{"vendor": "traefik", "product": "traefik", "versions": [{"status": "affected", "version": "0", "lessThan": "2.11.55", "versionType": "semver"}, {"status": "unaffected", "version": "2.11.55", "versionType": "semver"}], "packageURL": "pkg:golang/github.com/traefik/traefik/v2", "defaultStatus": "unaffected"}, {"vendor": "traefik", "product": "traefik", "versions": [{"status": "affected", "version": "3.0.0", "versionType": "semver", "lessThanOrEqual": "3.7.10"}], "packageURL": "pkg:golang/github.com/traefik/traefik/v3", "defaultStatus": "unaffected"}], "datePublic": "2026-08-21T00:00:00.000Z", "references": [{"url": "https://github.com/traefik/traefik/security/advisories/GHSA-g55h-rg46-x9c5", "name": "GitHub Security Advisory (GHSA-g55h-rg46-x9c5)", "tags": ["vendor-advisory"]}, {"url": "https://www.vulncheck.com/advisories/traefik-before-2.11.55-mtls-bypass-via-tls-option-conflict", "name": "VulnCheck Advisory: Traefik before v2.11.55 mTLS Bypass via TLS Option Conflict", "tags": ["third-party-advisory"]}], "x_generator": {"engine": "vulncheck-endgame"}, "descriptions": [{"lang": "en", "value": "Traefik before v2.11.55 and v3.0.0 through v3.7.10 contain a TLS option conflict resolution vulnerability that allows unauthenticated attackers to bypass client-certificate authentication by creating conflicting TLS options on multi-host routers. Attackers can reach protected backends by exploiting shared TLS resolution across multiple hostnames in a single router rule, causing the strict mTLS requirement to fall back to default options for all hosts."}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-863", "description": "Incorrect Authorization"}]}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "2.11.55"}], "operator": "OR"}]}, {"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndIncluding": "3.7.12", "versionStartIncluding": "3.0.0"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-10-08T15:51:49.372Z"}}}, "cveMetadata": {"cveId": "CVE-2026-85597", "state": "PUBLISHED", "dateUpdated": "2026-10-08T15:51:49.372Z", "dateReserved": "2026-09-04T11:00:28.730Z", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "datePublished": "2026-09-04T11:30:00.783Z", "assignerShortName": "VulnCheck"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "packageURL": "pkg:golang/github.com/traefik/traefik/v2", "product": "traefik", "vendor": "traefik", "versions": [{"lessThan": "2.11.55", "status": "affected", "version": "0", "versionType": "semver"}, {"status": "unaffected", "version": "2.11.55", "versionType": "semver"}]}, {"defaultStatus": "unaffected", "packageURL": "pkg:golang/github.com/traefik/traefik/v3", "product": "traefik", "vendor": "traefik", "versions": [{"lessThanOrEqual": "3.7.10", "status": "affected", "version": "3.0.0", "versionType": "semver"}]}], "source": "disclosure@vulncheck.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*", "matchCriteriaId": "5322E1E1-46C7-443C-BD3C-5196194D8A90", "versionEndExcluding": "2.11.55", "vulnerable": true}, {"criteria": "cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*", "matchCriteriaId": "F15D5766-74A9-47EA-AB54-7937D39B17BC", "versionEndExcluding": "3.7.11", "versionStartIncluding": "3.0.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Traefik before v2.11.55 and v3.0.0 through v3.7.10 contain a TLS option conflict resolution vulnerability that allows unauthenticated attackers to bypass client-certificate authentication by creating conflicting TLS options on multi-host routers. Attackers can reach protected backends by exploiting shared TLS resolution across multiple hostnames in a single router rule, causing the strict mTLS requirement to fall back to default options for all hosts."}], "id": "CVE-2026-85597", "lastModified": "2026-10-08T16:17:55.807", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 9.1, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.2, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.2, "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": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/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": "NONE", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "disclosure@vulncheck.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-85597", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-09-04T18:03:53.030722Z", "version": "2.0.3"}}]}, "published": "2026-09-04T12:17:23.210", "references": [{"source": "disclosure@vulncheck.com", "tags": ["Exploit", "Mitigation", "Patch", "Vendor Advisory"], "url": "https://github.com/traefik/traefik/security/advisories/GHSA-g55h-rg46-x9c5"}, {"source": "disclosure@vulncheck.com", "tags": ["Third Party Advisory"], "url": "https://www.vulncheck.com/advisories/traefik-before-2.11.55-mtls-bypass-via-tls-option-conflict"}], "sourceIdentifier": "disclosure@vulncheck.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-863"}], "source": "disclosure@vulncheck.com", "type": "Secondary"}]}

{"bugzilla": {"description": "github.com/traefik/traefik: Traefik: Authentication bypass via TLS option conflict", "id": "2528835", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2528835"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "status": "draft"}, "cwe": "CWE-303", "details": ["Traefik before v2.11.55 and v3.0.0 through v3.7.10 contain a TLS option conflict resolution vulnerability that allows unauthenticated attackers to bypass client-certificate authentication by creating conflicting TLS options on multi-host routers. Attackers can reach protected backends by exploiting shared TLS resolution across multiple hostnames in a single router rule, causing the strict mTLS requirement to fall back to default options for all hosts.", "A flaw was found in Traefik. This vulnerability allows unauthenticated attackers to bypass client-certificate authentication. By creating conflicting Transport Layer Security (TLS) options on multi-host routers, attackers can exploit shared TLS resolution across multiple hostnames in a single router rule. This causes the strict mutual TLS (mTLS) requirement to fall back to default options, enabling access to protected backends."], "mitigation": {"lang": "en:us", "value": "Separate multi-host router rules into dedicated single-host routers so each domain explicitly defines its required TLS options without inheritance conflicts. Alternatively, enforce client-certificate authentication at an upstream ingress controller or API gateway before traffic reaches the Traefik router."}, "name": "CVE-2026-85597", "package_state": [{"cpe": "cpe:/a:redhat:openshift_devspaces:3", "fix_state": "Affected", "package_name": "devspaces/traefik-rhel9", "product_name": "Red Hat OpenShift Dev Spaces"}, {"cpe": "cpe:/a:redhat:openshift_gitops:1", "fix_state": "Not affected", "package_name": "openshift-gitops-1/argo-rollouts-rhel8", "product_name": "Red Hat OpenShift GitOps"}, {"cpe": "cpe:/a:redhat:openshift_gitops:1", "fix_state": "Not affected", "package_name": "openshift-gitops-1/argo-rollouts-rhel9", "product_name": "Red Hat OpenShift GitOps"}], "public_date": "2026-09-04T11:30:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-85597\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-85597\nhttps://github.com/traefik/traefik/security/advisories/GHSA-g55h-rg46-x9c5\nhttps://www.vulncheck.com/advisories/traefik-before-2.11.55-mtls-bypass-via-tls-option-conflict"], "statement": "A flaw was found in Traefik before v2.11.55 and v3.0.0 through v3.7.10, where multi-host router configurations fail to isolate TLS options. When shared router rules encompass multiple hostnames, conflicting TLS settings cause strict mTLS enforcement to regress to default configuration parameters across all associated endpoints. Within Red Hat environments utilizing affected Traefik versions, an unauthenticated remote attacker can exploit this fallback behavior to bypass client-certificate authentication controls and access protected backend services without valid credentials.", "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "[0,2.11.55)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "2.11.55"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "traefik", "source": "cna", "vendor": "traefik"}, "product": "traefik", "vendor": "traefik"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[3.0.0,3.7.12]"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "traefik", "source": "cna", "vendor": "traefik"}, "product": "traefik", "vendor": "traefik"}], "created": "2026-09-04T12:45:03.852731+00:00", "updated": "2026-09-11T06:45:06.502272+00:00", "vendors": ["traefik", "traefik$PRODUCT$traefik"]}