{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-2833", "assignerOrgId": "a22f1246-ba21-4bb4-a601-ad51614c1513", "state": "PUBLISHED", "assignerShortName": "cloudflare", "dateReserved": "2026-02-19T21:02:12.382Z", "datePublished": "2026-03-04T23:20:51.985Z", "dateUpdated": "2026-03-04T23:20:51.985Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "https://github.com/cloudflare/pingora", "repo": "https://github.com/cloudflare/pingora", "vendor": "Cloudflare", "versions": [{"lessThan": "0.8.0", "status": "affected", "version": "0", "versionType": "semver"}]}], "credits": [{"lang": "en", "type": "reporter", "value": "Rajat Raghav (xclow3n)"}], "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<span style=\"background-color: transparent;\">An HTTP request smuggling vulnerability (CWE-444) was found in Pingora's handling of HTTP/1.1 connection upgrades. The issue occurs when a Pingora proxy reads a request containing an Upgrade header, causing the proxy to pass through the rest of the bytes on the connection to a backend before the backend has accepted the upgrade. An attacker can thus directly forward a malicious payload after a request with an Upgrade header to that backend in a way that may be interpreted as a subsequent request header, bypassing proxy-level security controls and enabling cross-user session hijacking.<br><br></span><p><span style=\"background-color: transparent;\">Impact</span></p><p><span style=\"background-color: transparent;\">This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to:</span></p><ul><li><p><span style=\"background-color: transparent;\">Bypass proxy-level ACL controls and WAF logic</span></p></li></ul><ul><li><p><span style=\"background-color: transparent;\">Poison caches and upstream connections, causing subsequent requests from legitimate users to receive responses intended for smuggled requests</span></p></li></ul><ul><li><p><span style=\"background-color: transparent;\">Perform cross-user attacks by hijacking sessions or smuggling requests that appear to originate from the trusted proxy IP</span></p></li></ul><p><span style=\"background-color: transparent;\">Cloudflare's CDN infrastructure was not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.</span></p><br><p><span style=\"background-color: transparent;\">Mitigation:</span></p><p><span style=\"background-color: transparent;\">Pingora users should upgrade to Pingora v0.8.0 or higher</span><span style=\"background-color: transparent;\"><br></span></p><b></b><p><span style=\"background-color: transparent;\">As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.</span></p>"}], "value": "An HTTP request smuggling vulnerability (CWE-444) was found in Pingora's handling of HTTP/1.1 connection upgrades. The issue occurs when a Pingora proxy reads a request containing an Upgrade header, causing the proxy to pass through the rest of the bytes on the connection to a backend before the backend has accepted the upgrade. An attacker can thus directly forward a malicious payload after a request with an Upgrade header to that backend in a way that may be interpreted as a subsequent request header, bypassing proxy-level security controls and enabling cross-user session hijacking.\n\nImpact\n\nThis vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to:\n\n * Bypass proxy-level ACL controls and WAF logic\n\n\n\n\n * Poison caches and upstream connections, causing subsequent requests from legitimate users to receive responses intended for smuggled requests\n\n\n\n\n * Perform cross-user attacks by hijacking sessions or smuggling requests that appear to originate from the trusted proxy IP\n\n\n\n\nCloudflare's CDN infrastructure was not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.\n\n\nMitigation:\n\nPingora users should upgrade to Pingora v0.8.0 or higher\n\n\nAs a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse."}], "metrics": [{"cvssV4_0": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "baseScore": 9.3, "baseSeverity": "CRITICAL", "exploitMaturity": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-444", "description": "CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "a22f1246-ba21-4bb4-a601-ad51614c1513", "shortName": "cloudflare", "dateUpdated": "2026-03-04T23:20:51.985Z"}, "references": [{"url": "https://github.com/cloudflare/pingora"}], "solutions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "Pingora users should upgrade to Pingora v0.8.0 or higher<br>"}], "value": "Pingora users should upgrade to Pingora v0.8.0 or higher"}], "source": {"discovery": "UNKNOWN"}, "title": "HTTP Request Smuggling via Premature Upgrade", "workarounds": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.<br>"}], "value": "As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse."}], "x_generator": {"engine": "Vulnogram 0.5.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "An HTTP request smuggling vulnerability (CWE-444) was found in Pingora's handling of HTTP/1.1 connection upgrades. The issue occurs when a Pingora proxy reads a request containing an Upgrade header, causing the proxy to pass through the rest of the bytes on the connection to a backend before the backend has accepted the upgrade. An attacker can thus directly forward a malicious payload after a request with an Upgrade header to that backend in a way that may be interpreted as a subsequent request header, bypassing proxy-level security controls and enabling cross-user session hijacking.\n\nImpact\n\nThis vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to:\n\n * Bypass proxy-level ACL controls and WAF logic\n\n\n\n\n * Poison caches and upstream connections, causing subsequent requests from legitimate users to receive responses intended for smuggled requests\n\n\n\n\n * Perform cross-user attacks by hijacking sessions or smuggling requests that appear to originate from the trusted proxy IP\n\n\n\n\nCloudflare's CDN infrastructure was not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.\n\n\nMitigation:\n\nPingora users should upgrade to Pingora v0.8.0 or higher\n\n\nAs a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse."}], "id": "CVE-2026-2833", "lastModified": "2026-03-05T00:15:57.650", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 9.3, "baseSeverity": "CRITICAL", "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": "HIGH", "subIntegrityImpact": "HIGH", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/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": "NONE", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "cna@cloudflare.com", "type": "Secondary"}]}, "published": "2026-03-05T00:15:57.650", "references": [{"source": "cna@cloudflare.com", "url": "https://github.com/cloudflare/pingora"}], "sourceIdentifier": "cna@cloudflare.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-444"}], "source": "cna@cloudflare.com", "type": "Secondary"}]}

{}

{}