{"id":"CVE-2017-7521","aliases":["DEBIAN-CVE-2017-7521","DSA-3900-1","EUVD-2017-16538","GHSA-mmxr-6344-9fv5","MGASA-2017-0224","SUSE-SU-2017:1635-1","SUSE-SU-2017:1718-1","UBUNTU-CVE-2017-7521","USN-3339-1","openSUSE-SU-2024:11128-1"],"status":"published","title":"OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to remote denial-of-service due to...","description":"OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to remote denial-of-service due to memory exhaustion caused by memory leaks and double-free issue in extract_x509_extension().","severity":{"version":"3.0","score":5.9,"vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-08","score":0.03855,"percentile":0.90231,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-400","CWE-415","CWE-772"],"published":"2017-06-21T00:00:00Z","modified":"2026-10-24T10:30:18Z","fixes":[{"ecosystem":"Debian:12","package":"openvpn","fixed_in":["2.4.3-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"openvpn","fixed_in":["2.4.3-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"openvpn","fixed_in":["2.4.3-1"],"sources":["osv"]},{"ecosystem":"Ubuntu:14.04:LTS","package":"openvpn","fixed_in":["2.3.2-7ubuntu3.2"],"sources":["osv"]},{"ecosystem":"Ubuntu:16.04:LTS","package":"openvpn","fixed_in":["2.3.10-1ubuntu2.1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.3-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.3-1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.3-1"}]}]},{"source":"osv","ecosystem":"Debian:8","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.4-5+deb8u2"}]}],"versions":["2.3.4-5","2.3.4-5+deb8u1"],"bundled":3},{"source":"osv","ecosystem":"Debian:9","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.4.0-6+deb9u1"}]}],"versions":["2.4.0-6","2.4.0-6+deb9u1~bpo8+1"],"bundled":3},{"source":"osv","ecosystem":"Mageia:5","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.17-1.mga5"}]}],"bundled":4},{"source":"osv","ecosystem":"SUSE:OpenStack Cloud 6","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.8-16.17.1"}]}],"bundled":3},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Desktop 12 SP2","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.8-16.17.1"}]}],"bundled":3},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server for Raspberry Pi 12 SP2","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.8-16.17.1"}]}],"bundled":3},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server for SAP Applications 12","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.8-16.17.1"}]}],"bundled":3},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server for SAP Applications 12 SP1","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.8-16.17.1"}]}],"bundled":3},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server 12-LTSS","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.8-16.17.1"}]}],"bundled":3},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server 12 SP1-LTSS","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.8-16.17.1"}]}],"bundled":3},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server 12 SP2","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.8-16.17.1"}]}],"bundled":3},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server for SAP Applications 12 SP2","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.8-16.17.1"}]}],"bundled":3},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server 11-SECURITY","package":"openvpn-openssl1","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.2-0.9.1"}]}],"bundled":5},{"source":"osv","ecosystem":"Ubuntu:14.04:LTS","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.2-7ubuntu3.2"}]}],"versions":["2.3.2-4ubuntu1","2.3.2-5ubuntu1","2.3.2-7ubuntu1","2.3.2-7ubuntu2","2.3.2-7ubuntu3","2.3.2-7ubuntu3.1"]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.10-1ubuntu2.1"}]}],"versions":["2.3.7-1ubuntu1","2.3.7-2ubuntu1","2.3.8-1ubuntu1","2.3.10-1ubuntu1","2.3.10-1ubuntu2"]},{"source":"osv","ecosystem":"Ubuntu:14.04:LTS","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.2-7ubuntu3.2"}]}],"versions":["2.3.2-4ubuntu1","2.3.2-5ubuntu1","2.3.2-7ubuntu1","2.3.2-7ubuntu2","2.3.2-7ubuntu3","2.3.2-7ubuntu3.1"],"bundled":5},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.3.10-1ubuntu2.1"}]}],"versions":["2.3.7-1ubuntu1","2.3.7-2ubuntu1","2.3.8-1ubuntu1","2.3.10-1ubuntu1","2.3.10-1ubuntu2"],"bundled":5},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"openvpn","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.3-1.2"}]}],"bundled":10}],"products":[{"vendor":"openvpn","product":"openvpn"},{"vendor":"openvpn technologies, inc","product":"openvpn"}],"references":[{"url":"https://community.openvpn.net/openvpn/wiki/VulnerabilitiesFixedInOpenVPN243","tags":["x_refsource_CONFIRM","x_transferred","Vendor Advisory","advisory","web","report"]},{"url":"http://www.securitytracker.com/id/1038768","tags":["vdb-entry","x_refsource_SECTRACK","x_transferred","web"]},{"url":"http://www.securityfocus.com/bid/99230","tags":["vdb-entry","x_refsource_BID","x_transferred","Third Party Advisory","VDB Entry","advisory"]},{"url":"http://www.debian.org/security/2017/dsa-3900","tags":["vendor-advisory","x_refsource_DEBIAN","x_transferred","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2017-7521"},{"url":"https://github.com/advisories/GHSA-mmxr-6344-9fv5"},{"url":"https://security-tracker.debian.org/tracker/CVE-2017-7521","tags":["advisory"]},{"url":"https://advisories.mageia.org/MGASA-2017-0224.html","tags":["advisory"]},{"url":"https://bugs.mageia.org/show_bug.cgi?id=21125","tags":["report"]},{"url":"https://lists.opensuse.org/opensuse-security-announce/2017-06/msg00027.html","tags":["web"]},{"url":"https://www.ubuntu.com/usn/usn-3339-1/","tags":["web"]},{"url":"https://www.suse.com/support/update/announcement/2017/suse-su-20171635-1/","tags":["advisory"]},{"url":"https://bugzilla.suse.com/1044947","tags":["report"]},{"url":"https://www.suse.com/security/cve/CVE-2017-7508","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-7520","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-7521","tags":["web"]},{"url":"https://www.suse.com/support/update/announcement/2017/suse-su-20171718-1/","tags":["advisory"]},{"url":"https://bugzilla.suse.com/1038709","tags":["report"]},{"url":"https://bugzilla.suse.com/1038711","tags":["report"]},{"url":"https://bugzilla.suse.com/1038713","tags":["report"]},{"url":"https://bugzilla.suse.com/959511","tags":["report"]},{"url":"https://bugzilla.suse.com/988522","tags":["report"]},{"url":"https://www.suse.com/security/cve/CVE-2017-7478","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-7479","tags":["web"]},{"url":"https://ubuntu.com/security/CVE-2017-7521","tags":["report"]},{"url":"http://www.openwall.com/lists/oss-security/2017/06/21/6","tags":["report"]},{"url":"https://ubuntu.com/security/notices/USN-3339-1","tags":["advisory"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2017-7521","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2016-6329","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2017-7479","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2017-7508","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2017-7520","tags":["report"]},{"url":"","tags":["advisory"]},{"url":"https://www.suse.com/security/cve/CVE-2005-3393","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2005-3409","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2006-1629","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2006-4339","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-12166","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2017-7522","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2018-9336","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-11810","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2020-15078","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2017-7521","description":"OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to remote denial-of-service due to memory exhaustion caused by memory leaks and double-free issue in extract_x509_extension().","status":"published","published":"2017-06-27T13:00:00Z","modified":"2024-08-05T16:04:11.856Z","cwes":["CWE-400"],"updated_at":"2026-11-02T14:33:20.488433Z"}],"euvd":[{"id":"EUVD-2017-16538","description":"OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to remote denial-of-service due to memory exhaustion caused by memory leaks and double-free issue in extract_x509_extension().","status":"published","published":"2017-06-27T13:00:00Z","modified":"2024-08-05T16:04:11Z","updated_at":"2026-11-03T02:39:08.024596Z"}],"ghsa":[{"id":"GHSA-mmxr-6344-9fv5","title":"OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to remote denial-of-service due to...","description":"OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to remote denial-of-service due to memory exhaustion caused by memory leaks and double-free issue in extract_x509_extension().","status":"published","published":"2022-05-13T01:47:00Z","modified":"2025-04-20T03:39:33Z","cvss":[{"version":"3.0","score":5.9,"vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-400","CWE-415"],"updated_at":"2026-11-02T15:01:47.375435Z"}],"nvd":[{"id":"CVE-2017-7521","description":"OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to remote denial-of-service due to memory exhaustion caused by memory leaks and double-free issue in extract_x509_extension().","status":"published","published":"2017-06-27T13:29:00.24Z","modified":"2026-06-17T01:24:31.153Z","cvss":[{"version":"3.0","score":5.9,"vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-400","CWE-415","CWE-772"],"updated_at":"2026-11-02T14:03:51.893212Z"}],"osv":[{"id":"CVE-2017-7521","description":"OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to remote denial-of-service due to memory exhaustion caused by memory leaks and double-free issue in extract_x509_extension().","status":"published","published":"2017-06-27T13:29:00.24Z","modified":"2026-10-24T10:30:18.48143103Z","cvss":[{"version":"3.0","score":5.9,"vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:44:06.412595Z"},{"id":"DEBIAN-CVE-2017-7521","description":"OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to remote denial-of-service due to memory exhaustion caused by memory leaks and double-free issue in extract_x509_extension().","status":"published","published":"2017-06-27T13:29:00.24Z","modified":"2026-09-01T20:03:50.143712136Z","cvss":[{"version":"3.0","score":5.9,"vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:45:29.412243Z"},{"id":"UBUNTU-CVE-2017-7521","description":"OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to remote denial-of-service due to memory exhaustion caused by memory leaks and double-free issue in extract_x509_extension().","status":"published","published":"2017-06-21T00:00:00Z","modified":"2026-02-04T02:48:12.642249Z","cvss":[{"version":"3.0","score":5.9,"vector":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:54:15.773974Z"},{"id":"DSA-3900-1","title":"openvpn - security update","status":"published","published":"2017-06-27T00:00:00Z","modified":"2026-03-09T01:18:29.134286Z","updated_at":"2026-11-02T15:46:16.523846Z"},{"id":"MGASA-2017-0224","title":"Updated openvpn packages fix security vulnerabilities","description":"It was possible to trigger an assertion by sending a malformed IPv6\npacket. That issue could have been abused to remotely shutdown an\nopenvpn server or client, if IPv6 and --mssfix were enabled and if the\nIPv6 networks used inside the VPN were known (CVE-2017-7508).\n\nSome parts of the certificate-parsing code did not always clear all\nallocated memory. This would have allowed clients to leak a few bytes of\nmemory for each connection attempt, thereby facilitating a (quite\ninefficient) DoS attack on the server (CVE-2017-7512).\n\nIf clients used a HTTP proxy with NTLM authentication, a\nman-in-the-middle attacker between client and proxy could cause the\nclient to crash or disclose at most 96 bytes of stack memory. The\ndisclosed stack memory was likely to contain the proxy password. If the\nproxy password had not been reused, this was unlikely to compromise the\nsecurity of the OpenVPN tunnel itself. Clients who did not use the\n--http-proxy option with ntlm2 authentication were not affected\n(CVE-2017-7520).\n\nThe ASN1 parsing code contained a bug that could have resulted in some\nbuffers being free()d twice, and this issue could have potentially been\ntriggered remotely by a VPN peer (CVE-2017-7521).\n","status":"published","published":"2017-07-28T18:12:15Z","modified":"2026-04-16T06:23:39.550256709Z","updated_at":"2026-11-02T15:49:40.103088Z"},{"id":"openSUSE-SU-2024:11128-1","title":"openvpn-2.5.3-1.2 on GA media","description":"These are all security issues fixed in the openvpn-2.5.3-1.2 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2024-06-15T00:00:00Z","modified":"2026-02-04T03:53:06.953443Z","updated_at":"2026-11-02T16:58:34.894275Z"},{"id":"SUSE-SU-2017:1635-1","title":"Security update for openvpn","description":"This update for openvpn fixes the following issues:\n\n- Some parts of the certificate-parsing code did not always clear all allocated\n  memory. This would have allowed clients to leak a few bytes of memory for\n  each connection attempt, thereby facilitating a (quite inefficient) DoS\n  attack on the server. [bsc#1044947, CVE-2017-7521]\n\n- The ASN1 parsing code contained a bug that could have resulted in some\n  buffers being free()d twice, and this issue could have potentially been\n  triggered remotely by a VPN peer. [bsc#1044947, CVE-2017-7521]\n\n- If clients used a HTTP proxy with NTLM authentication, a man-in-the-middle\n  attacker between client and proxy could cause the client to crash or disclose\n  at most 96 bytes of stack memory. The disclosed stack memory was likely to\n  contain the proxy password. If the proxy password had not been reused, this\n  was unlikely to compromise the security of the OpenVPN tunnel itself. Clients\n  who did not use the --http-proxy option with ntlm2 authentication were not\n  affected. [bsc#1044947, CVE-2017-7520]\n\n- It was possible to trigger an assertion by sending a malformed IPv6 packet.\n  That issue could have been abused to remotely shutdown an openvpn server or\n  client, if IPv6 and --mssfix were enabled and if the IPv6 networks used\n  inside the VPN were known. [bsc#1044947, CVE-2017-7508]\n","status":"published","published":"2017-06-21T11:51:57Z","modified":"2026-02-04T03:24:38.701243Z","updated_at":"2026-11-02T15:53:43.83457Z"},{"id":"SUSE-SU-2017:1718-1","title":"Security update for openvpn-openssl1","description":"This update for openvpn-openssl1 fixes the following issues:\n\n- Some parts of the certificate-parsing code did not always clear all allocated\n  memory. This would have allowed clients to leak a few bytes of memory for\n  each connection attempt, thereby facilitating a (quite inefficient) DoS\n  attack on the server. [bsc#1044947, CVE-2017-7521]\n\n- The ASN1 parsing code contained a bug that could have resulted in some\n  buffers being free()d twice, and this issue could have potentially been\n  triggered remotely by a VPN peer. [bsc#1044947, CVE-2017-7521]\n\n- If clients used a HTTP proxy with NTLM authentication, a man-in-the-middle\n  attacker between client and proxy could cause the client to crash or disclose\n  at most 96 bytes of stack memory. The disclosed stack memory was likely to\n  contain the proxy password. If the proxy password had not been reused, this\n  was unlikely to compromise the security of the OpenVPN tunnel itself. Clients\n  who did not use the --http-proxy option with ntlm2 authentication were not\n  affected. [bsc#1044947, CVE-2017-7520]\n\n- It was possible to trigger an assertion by sending a malformed IPv6 packet.\n  That issue could have been abused to remotely shutdown an openvpn server or\n  client, if IPv6 and --mssfix were enabled and if the IPv6 networks used\n  inside the VPN were known. [bsc#1044947, CVE-2017-7508]\n\n- The installed sample configuration file was updated to comply to FIPS\n  requirements. [bsc#988522]\n\n- Remedy large latencies on the openVPN server during authentication process.\n  [bsc#959511]\n\n- Fix potential denial-of-service attacks found during independent audits.\n  [bsc#1038713, bsc#1038709, CVE-2017-7478, bsc#1038711, CVE-2017-7479]\n","status":"published","published":"2017-06-29T11:41:38Z","modified":"2026-02-04T04:03:27.717118Z","updated_at":"2026-11-02T15:53:44.209561Z"},{"id":"USN-3339-1","title":"openvpn vulnerabilities","description":"Karthikeyan Bhargavan and Gaëtan Leurent discovered that 64-bit block\nciphers are vulnerable to a birthday attack. A remote attacker could\npossibly use this issue to recover cleartext data. Fixing this issue\nrequires a configuration change to switch to a different cipher. This\nupdate adds a warning to the log file when a 64-bit block cipher is in use.\nThis issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS and\nUbuntu 16.10. (CVE-2016-6329)\n\nIt was discovered that OpenVPN incorrectly handled rollover of packet ids.\nAn authenticated remote attacker could use this issue to cause OpenVPN to\ncrash, resulting in a denial of service. This issue only affected Ubuntu\n14.04 LTS, Ubuntu 16.04 LTS and Ubuntu 16.10. (CVE-2017-7479)\n\nGuido Vranken discovered that OpenVPN incorrectly handled certain malformed\nIPv6 packets. A remote attacker could use this issue to cause OpenVPN to\ncrash, resulting in a denial of service. (CVE-2017-7508)\n\nGuido Vranken discovered that OpenVPN incorrectly handled an HTTP proxy\nwith NTLM authentication. A remote attacker could use this issue to cause\nOpenVPN clients to crash, resulting in a denial of service, or possibly\nexpose sensitive memory contents. (CVE-2017-7520)\n\nGuido Vranken discovered that OpenVPN incorrectly handled certain x509\nextensions. A remote attacker could use this issue to cause OpenVPN to\ncrash, resulting in a denial of service. (CVE-2017-7521)\n\n","status":"published","published":"2017-06-22T18:02:03Z","modified":"2026-02-10T04:41:09Z","updated_at":"2026-11-02T16:58:13.496563Z"}]}}