{"id":"CVE-2026-33523","state":"PUBLISHED","title":"Apache HTTP Server: multiple modules: HTTP response splitting forwarding malicious status line","description":"HTTP response splitting vulnerability in multiple Apache HTTP Server modules with untrusted or compromised backend servers.\n\nThis issue affects Apache HTTP Server: from through 2.4.66.\n\nUsers are recommended to upgrade to version 2.4.67, which fixes the issue.","publishedAt":"2026-05-04T14:40:41.430Z","updatedAt":"2026-05-04T17:32:49.282Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","source":"CISA-ADP"},"assigner":"apache","products":["Apache Software Foundation Apache HTTP Server"],"affected":[{"vendor":"Apache Software Foundation","product":"Apache HTTP Server","defaultStatus":"unaffected","versions":[{"version":"2.4.0","status":"affected","lessThanOrEqual":"2.4.66","versionType":"semver"}]}],"references":["https://httpd.apache.org/security/vulnerabilities_24.html","http://www.openwall.com/lists/oss-security/2026/05/04/23"],"weaknesses":["CWE-443"],"ingestedAt":"2026-10-29T20:11:40.391Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/33xxx/CVE-2026-33523.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-33523","state":"PUBLISHED","datePublished":"2026-05-04T14:40:41.430Z","dateUpdated":"2026-05-04T17:32:49.282Z","assignerShortName":"apache","assignerOrgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","dateReserved":"2026-03-20T17:29:39.696Z"},"containers":{"cna":{"title":"Apache HTTP Server: multiple modules: HTTP response splitting forwarding malicious status line","descriptions":[{"lang":"en","value":"HTTP response splitting vulnerability in multiple Apache HTTP Server modules with untrusted or compromised backend servers.\n\nThis issue affects Apache HTTP Server: from through 2.4.66.\n\nUsers are recommended to upgrade to version 2.4.67, which fixes the issue."}],"affected":[{"vendor":"Apache Software Foundation","product":"Apache HTTP Server","defaultStatus":"unaffected","versions":[{"version":"2.4.0","status":"affected","lessThanOrEqual":"2.4.66","versionType":"semver"}]}],"references":[{"url":"https://httpd.apache.org/security/vulnerabilities_24.html","tags":["vendor-advisory"]}],"metrics":[{"other":{"content":{"text":"low"},"type":"Textual description of severity"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-443","description":"CWE-443: HTTP response splitting","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"apache","orgId":"f0158376-9dc2-43b6-827c-5f631a4d8d09","dateUpdated":"2026-05-04T14:40:41.430Z"},"credits":[{"lang":"en","type":"finder","value":"Haruki Oyama (Waseda University)"},{"lang":"en","type":"finder","value":"Merih Mengisteab"},{"lang":"en","type":"finder","value":"Dawit Jeong"}],"source":{"discovery":"UNKNOWN"},"timeline":[{"lang":"en","time":"2026-03-05T12:00:00.000Z","value":"reported"},{"lang":"eng","time":"2026-05-04T12:00:00.000Z","value":"2.4.67 released"},{"lang":"en","time":"2026-05-04T12:00:00.000Z","value":"fixed in 2.4.x by r1933360"}],"x_generator":{"engine":"Vulnogram 0.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":6.5,"attackVector":"NETWORK","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","integrityImpact":"LOW","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"LOW"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-05-04T15:55:00.471385Z","id":"CVE-2026-33523","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-04T15:56:35.673Z"}},{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/05/04/23"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-05-04T17:32:49.282Z"}}]}}}