CVE-2026-31842

{"id": "CVE-2026-31842", "cveTags": [], "metrics": {"cvssMetricV2": [{"type": "Secondary", "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c", "cvssData": {"version": "2.0", "baseScore": 7.8, "accessVector": "NETWORK", "vectorString": "AV:N/AC:L/Au:N/C:N/I:N/A:C", "authentication": "NONE", "integrityImpact": "NONE", "accessComplexity": "LOW", "availabilityImpact": "COMPLETE", "confidentialityImpact": "NONE"}, "acInsufInfo": false, "impactScore": 6.9, "baseSeverity": "HIGH", "obtainAllPrivilege": false, "exploitabilityScore": 10.0, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}], "cvssMetricV31": [{"type": "Secondary", "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.7, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "published": "2026-04-07T12:16:21.040", "references": [{"url": "https://datatracker.ietf.org/doc/html/rfc7230", "tags": ["Exploit", "Technical Description"], "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"}, {"url": "https://github.com/tinyproxy/tinyproxy", "tags": ["Product"], "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"}, {"url": "https://github.com/tinyproxy/tinyproxy/issues/604", "tags": ["Exploit", "Issue Tracking"], "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c", "description": [{"lang": "en", "value": "CWE-444"}]}], "descriptions": [{"lang": "en", "value": "Tinyproxy through 1.11.3 is vulnerable to HTTP request parsing desynchronization due to a case-sensitive comparison of the Transfer-Encoding header in src/reqs.c. The is_chunked_transfer() function uses strcmp() to compare the header value against \"chunked\", even though RFC 7230 specifies that transfer-coding names are case-insensitive. By sending a request with Transfer-Encoding: Chunked, an unauthenticated remote attacker can cause Tinyproxy to misinterpret the request as having no body. In this state, Tinyproxy sets content_length.client to -1, skips pull_client_data_chunked(), forwards request headers upstream, and transitions into relay_connection() raw TCP forwarding while unread body data remains buffered. This leads to inconsistent request state between Tinyproxy and backend servers. RFC-compliant backends (e.g., Node.js, Nginx) will continue waiting for chunked body data, causing connections to hang indefinitely. This behavior enables application-level denial of service through backend worker exhaustion. Additionally, in deployments where Tinyproxy is used for request-body inspection, filtering, or security enforcement, the unread body may be forwarded without proper inspection, resulting in potential security control bypass."}], "lastModified": "2026-04-29T18:51:51.030", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:tinyproxy_project:tinyproxy:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "47E38326-9534-404D-806F-11FF49FD0B0E", "versionEndIncluding": "1.11.3"}], "operator": "OR"}]}], "sourceIdentifier": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c"}