CVE-2026-33555

{"id": "CVE-2026-33555", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-33555", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-04-22T18:42:59.239377Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "cve@mitre.org", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 4.0, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 2.2}, {"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 5.8, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 3.9}]}, "affected": [{"source": "cve@mitre.org", "affectedData": [{"vendor": "HAProxy", "product": "HAProxy", "versions": [{"status": "affected", "version": "2.6", "lessThan": "3.3.6", "versionType": "custom"}], "defaultStatus": "unaffected"}]}], "published": "2026-04-13T17:16:28.237", "references": [{"url": "https://github.com/haproxy/haproxy/commit/05a295441c621089ffa4318daf0dbca2dd756a84", "tags": ["Patch"], "source": "cve@mitre.org"}, {"url": "https://r3verii.github.io/cve/2026/04/14/haproxy-h3-standalone-fin-smuggling.html", "tags": ["Exploit", "Third Party Advisory"], "source": "cve@mitre.org"}, {"url": "https://www.haproxy.com/documentation/haproxy-aloha/changelog/", "tags": ["Release Notes"], "source": "cve@mitre.org"}, {"url": "https://www.haproxy.org", "tags": ["Product"], "source": "cve@mitre.org"}, {"url": "https://www.mail-archive.com/haproxy@formilux.org/msg46752.html", "tags": ["Release Notes"], "source": "cve@mitre.org"}, {"url": "https://r3verii.github.io/cve/2026/04/14/haproxy-h3-standalone-fin-smuggling.html", "tags": ["Exploit", "Third Party Advisory"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "cve@mitre.org", "description": [{"lang": "en", "value": "CWE-130"}]}], "descriptions": [{"lang": "en", "value": "An issue was discovered in HAProxy before 3.3.6. The HTTP/3 parser does not check that the received body length matches a previously announced content-length when the stream is closed via a frame with an empty payload. This can cause desynchronization issues with the backend server and could be used for request smuggling. The earliest affected version is 2.6."}], "lastModified": "2026-06-29T15:28:15.663", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:haproxy:haproxy:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "B0C66EEE-8E91-4525-9187-0FB58152B8BC", "versionEndExcluding": "3.3.6", "versionStartIncluding": "2.6.0"}], "operator": "OR"}]}], "sourceIdentifier": "cve@mitre.org"}