{"id":"CVE-2020-17527","title":"While investigating bug 64830 it was discovered that Apache Tomcat 10.0.0-M1 to 10.0.0-M9, 9.0.0-M1 to 9.0.39 and 8.5.0 to 8.5.59 could re-use an HTTP request header value from the previous stream received on an HTTP/2 connection for the…","summary":"While investigating bug 64830 it was discovered that Apache Tomcat 10.0.0-M1 to 10.0.0-M9, 9.0.0-M1 to 9.0.39 and 8.5.0 to 8.5.59 could re-use an HTTP request header value from the previous stream received on an HTTP/2 connection for the…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","cwe":["CWE-200","CWE-200"],"vendor":"apache","product":"tomcat","affected":["tomcat >= 8.5.1, <= 8.5.59","tomcat >= 9.0.1, <= 9.0.35","tomcat = 9.0.0","tomcat = 9.0.35-3.39.1","tomcat = 9.0.35-3.57.3","tomcat = 9.0.36","tomcat = 9.0.37","tomcat = 9.0.38","tomcat = 9.0.39","tomcat = 10.0.0","element_plug-in","oncommand_system_manager >= 3.0.0, <= 3.1.3","debian_linux = 9.0","debian_linux = 10.0","blockchain_platform < 21.1.2","communications_cloud_native_core_binding_support_function = 1.10.0","communications_cloud_native_core_policy = 1.14.0","communications_instant_messaging_server = 10.0.1.5.0","instantis_enterprisetrack = 17.1","instantis_enterprisetrack = 17.2","instantis_enterprisetrack = 17.3","mysql_enterprise_monitor < 8.0.23","sd-wan_edge = 9.0","workload_manager = 18c","workload_manager = 19c"],"patched":["blockchain_platform 21.1.2","mysql_enterprise_monitor 8.0.23"],"published":"2020-12-03","updated":"2026-10-08","sourceUpdated":"2026-10-08T22:16:57.557","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2020-17527","references":[{"url":"http://www.openwall.com/lists/oss-security/2020/12/03/3","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r26a2a66339087fc37db3caf201e446d3e83b5cce314371e235ff1784%40%3Ccommits.tomee.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r2d6e05c5ff96f8068a59dfdb3800e9ee8d4e36ce1971783c6e5f9b20%40%3Ccommits.tomee.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r5a285242737ddef4d338236328aaaf3237183e1465a5efafd16b99ed%40%3Cdev.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r8a227ac6a755a6406c1cc47dd48800e973d4cf13fe7fe68ac59c679c%40%3Cdev.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/r9fd47f1b03e9b41d16a5cf72659b533887267d3398d963c2fff3abfa%40%3Ccommits.tomee.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/ra35c8d617b17d59f400112cebadec43ad379f98198b4a9726190d7ee%40%3Cissues.guacamole.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/ra9fcdb904dd2e2256ef90b3e4ced279cd464cb0ab63a6c64df5c010d%40%3Cannounce.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/ra9fcdb904dd2e2256ef90b3e4ced279cd464cb0ab63a6c64df5c010d%40%3Cannounce.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/raa0e9ad388c1e6fd1e301b5e080f9439f64cb4178119a86a4801cc53%40%3Cdev.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rabbe6b3ae6a9795641d7a05c00d2378d5bbbe4240b7e20f09b092cce%40%3Cissues.guacamole.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rbba08c4dcef3603e36276d49adda8eedbe458c5104314b4038f697e1%40%3Cusers.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rca833c6d42b7b9ce1563488c0929f29fcc95947d86e5e740258c8937%40%3Cdev.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rce5ac9a40173651d540babce59f6f3825f12c6d4e886ba00823b11e5%40%3Cannounce.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.apache.org/thread.html/rd5babd13d7a350b369b2f647b4dd32ce678af42f9aba5389df1ae6ca%40%3Cusers.tomcat.apache.org%3E","label":"security@apache.org"},{"url":"https://lists.debian.org/debian-lts-announce/2020/12/msg00022.html","label":"security@apache.org"},{"url":"https://security.gentoo.org/glsa/202012-23","label":"security@apache.org"},{"url":"https://security.netapp.com/advisory/ntap-20201210-0003/","label":"security@apache.org"},{"url":"https://www.debian.org/security/2021/dsa-4835","label":"security@apache.org"},{"url":"https://www.oracle.com//security-alerts/cpujul2021.html","label":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpuApr2021.html","label":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","label":"security@apache.org"},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","label":"security@apache.org"},{"url":"http://www.openwall.com/lists/oss-security/2020/12/03/3","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r26a2a66339087fc37db3caf201e446d3e83b5cce314371e235ff1784%40%3Ccommits.tomee.apache.org%3E","label":"af854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3:17:21.747Z"},"exploitAvailable":true,"ingestedAt":"2026-10-08T23:16:47.310Z","slug":"CVE-2020-17527","body":"## Overview\n\nWhile investigating bug 64830 it was discovered that Apache Tomcat 10.0.0-M1 to 10.0.0-M9, 9.0.0-M1 to 9.0.39 and 8.5.0 to 8.5.59 could re-use an HTTP request header value from the previous stream received on an HTTP/2 connection for the request associated with the subsequent stream. While this would most likely lead to an error and the closure of the HTTP/2 connection, it is possible that information could leak between requests.\n\n## Affected\n\n- `tomcat >= 8.5.1, <= 8.5.59`\n- `tomcat >= 9.0.1, <= 9.0.35`\n- `tomcat = 9.0.0`\n- `tomcat = 9.0.35-3.39.1`\n- `tomcat = 9.0.35-3.57.3`\n- `tomcat = 9.0.36`\n- `tomcat = 9.0.37`\n- `tomcat = 9.0.38`\n- `tomcat = 9.0.39`\n- `tomcat = 10.0.0`\n- `element_plug-in`\n- `oncommand_system_manager >= 3.0.0, <= 3.1.3`\n- `debian_linux = 9.0`\n- `debian_linux = 10.0`\n- `blockchain_platform < 21.1.2`\n- `communications_cloud_native_core_binding_support_function = 1.10.0`\n- `communications_cloud_native_core_policy = 1.14.0`\n- `communications_instant_messaging_server = 10.0.1.5.0`\n- `instantis_enterprisetrack = 17.1`\n- `instantis_enterprisetrack = 17.2`\n- `instantis_enterprisetrack = 17.3`\n- `mysql_enterprise_monitor < 8.0.23`\n- `sd-wan_edge = 9.0`\n- `workload_manager = 18c`\n- `workload_manager = 19c`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `blockchain_platform 21.1.2`\n- `mysql_enterprise_monitor 8.0.23`","depth":"midnight","depthScore":58,"depthScoreParts":{"impact":41.3,"likelihood":4.9,"exploitation":12,"ransomware":0},"changes":[]}