{"id":"CVE-2015-5400","aliases":["DEBIAN-CVE-2015-5400","DLA-286-1","DSA-3327-1","EUVD-2015-5356","GHSA-9pj4-fqm8-w5x7","MGASA-2015-0347","SUSE-SU-2016:2008-1","SUSE-SU-2016:2089-1","UBUNTU-CVE-2015-5400","openSUSE-SU-2024:10307-1"],"status":"published","title":"Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with...","description":"Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with cache_peer, which allows remote attackers to bypass intended restrictions and gain access to a backend proxy via a CONNECT request.","severity":{"version":"2.0","score":6.8,"vector":"AV:N/AC:M/Au:N/C:P/I:P/A:P","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-08","score":0.20844,"percentile":0.97564,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-264"],"published":"2015-07-30T00:00:00Z","modified":"2026-09-09T06:47:25Z","fixes":[{"ecosystem":"Debian:12","package":"squid","fixed_in":["4.1-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"squid","fixed_in":["4.1-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"squid","fixed_in":["4.1-1"],"sources":["osv"]},{"ecosystem":"Debian:6.0","package":"squid3","fixed_in":["3.1.6-1.2+squeeze5"],"sources":["osv"]},{"ecosystem":"Debian:7","package":"squid3","fixed_in":["3.1.20-2.2+deb7u3"],"sources":["osv"]},{"ecosystem":"Debian:8","package":"squid3","fixed_in":["3.4.8-6+deb8u1"],"sources":["osv"]},{"ecosystem":"Mageia:5","package":"squid","fixed_in":["3.4.13-1.1.mga5"],"sources":["osv"]},{"ecosystem":"Ubuntu:16.04:LTS","package":"squid3","fixed_in":["3.5.12-1ubuntu6"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"squid","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.1-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"squid","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.1-1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"squid","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.1-1"}]}]},{"source":"osv","ecosystem":"Debian:6.0","package":"squid3","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.1.6-1.2+squeeze5"}]}],"versions":["3.1.6-1.2","3.1.6-1.2+squeeze1","3.1.6-1.2+squeeze2","3.1.6-1.2+squeeze3","3.1.6-1.2+squeeze4"]},{"source":"osv","ecosystem":"Debian:7","package":"squid3","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.1.20-2.2+deb7u3"}]}],"versions":["3.1.20-2.2","3.1.20-2.2+deb7u1","3.1.20-2.2+deb7u2"]},{"source":"osv","ecosystem":"Debian:8","package":"squid3","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.4.8-6+deb8u1"}]}],"versions":["3.4.8-6"]},{"source":"osv","ecosystem":"Mageia:5","package":"squid","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.4.13-1.1.mga5"}]}]},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server 12 SP1","package":"squid","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.3.14-20.2"}]}],"bundled":16},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server for SAP Applications 12 SP1","package":"squid","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.3.14-20.2"}]}],"bundled":16},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server 11 SP4","package":"squid3","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.1.23-8.16.30.1"}]}],"bundled":25},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server for SAP Applications 11 SP4","package":"squid3","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.1.23-8.16.30.1"}]}],"bundled":25},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"squid3","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.5.12-1ubuntu6"}]}],"versions":["3.3.8-1ubuntu16","3.3.8-1ubuntu17"]},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"squid","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.5.22-1.1"}]}],"bundled":4}],"products":[{"vendor":"debian","product":"debian_linux"},{"vendor":"fedoraproject","product":"fedora"},{"vendor":"squid-cache","product":"squid"}],"references":[{"url":"http://www.openwall.com/lists/oss-security/2015/07/06/8","tags":["mailing-list","x_refsource_MLIST","x_transferred","web","report"]},{"url":"http://www.securitytracker.com/id/1032873","tags":["vdb-entry","x_refsource_SECTRACK","x_transferred","web"]},{"url":"http://lists.fedoraproject.org/pipermail/package-announce/2016-May/183598.html","tags":["vendor-advisory","x_refsource_FEDORA","x_transferred","web"]},{"url":"http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-13856.patch","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Vendor Advisory","advisory","evidence"]},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00010.html","tags":["vendor-advisory","x_refsource_SUSE","x_transferred","web"]},{"url":"http://www.openwall.com/lists/oss-security/2015/07/17/14","tags":["mailing-list","x_refsource_MLIST","x_transferred","Exploit","evidence"]},{"url":"http://www.openwall.com/lists/oss-security/2015/07/09/12","tags":["mailing-list","x_refsource_MLIST","x_transferred","web"]},{"url":"http://lists.opensuse.org/opensuse-updates/2016-08/msg00069.html","tags":["vendor-advisory","x_refsource_SUSE","x_transferred","web"]},{"url":"http://www.squid-cache.org/Versions/v3/3.1/changesets/squid-3.1-10494.patch","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Vendor Advisory","advisory","evidence"]},{"url":"http://www.openwall.com/lists/oss-security/2015/07/10/2","tags":["mailing-list","x_refsource_MLIST","x_transferred","web"]},{"url":"http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00040.html","tags":["vendor-advisory","x_refsource_SUSE","x_transferred","web"]},{"url":"http://www.squid-cache.org/Advisories/SQUID-2015_2.txt","tags":["x_refsource_CONFIRM","x_transferred","Vendor Advisory","advisory","web","report"]},{"url":"http://www.debian.org/security/2015/dsa-3327","tags":["vendor-advisory","x_refsource_DEBIAN","x_transferred","advisory"]},{"url":"http://www.securityfocus.com/bid/75553","tags":["vdb-entry","x_refsource_BID","x_transferred","web"]},{"url":"http://www.squid-cache.org/Versions/v3/3.4/changesets/squid-3.4-13225.patch","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Vendor Advisory","advisory","evidence"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2015-5400"},{"url":"https://github.com/advisories/GHSA-9pj4-fqm8-w5x7"},{"url":"https://security-tracker.debian.org/tracker/CVE-2015-5400","tags":["advisory"]},{"url":"https://advisories.mageia.org/MGASA-2015-0347.html","tags":["advisory"]},{"url":"https://bugs.mageia.org/show_bug.cgi?id=16304","tags":["report"]},{"url":"https://www.debian.org/security/2015/dsa-3327","tags":["web"]},{"url":"https://www.suse.com/support/update/announcement/2016/suse-su-20162008-1/","tags":["advisory"]},{"url":"https://bugzilla.suse.com/902197","tags":["report"]},{"url":"https://bugzilla.suse.com/929493","tags":["report"]},{"url":"https://bugzilla.suse.com/938715","tags":["report"]},{"url":"https://bugzilla.suse.com/955783","tags":["report"]},{"url":"https://bugzilla.suse.com/959290","tags":["report"]},{"url":"https://bugzilla.suse.com/963539","tags":["report"]},{"url":"https://bugzilla.suse.com/968392","tags":["report"]},{"url":"https://bugzilla.suse.com/968393","tags":["report"]},{"url":"https://bugzilla.suse.com/968394","tags":["report"]},{"url":"https://bugzilla.suse.com/968395","tags":["report"]},{"url":"https://bugzilla.suse.com/973782","tags":["report"]},{"url":"https://bugzilla.suse.com/973783","tags":["report"]},{"url":"https://bugzilla.suse.com/976553","tags":["report"]},{"url":"https://bugzilla.suse.com/976556","tags":["report"]},{"url":"https://bugzilla.suse.com/979008","tags":["report"]},{"url":"https://bugzilla.suse.com/979009","tags":["report"]},{"url":"https://bugzilla.suse.com/979010","tags":["report"]},{"url":"https://bugzilla.suse.com/979011","tags":["report"]},{"url":"https://www.suse.com/security/cve/CVE-2015-3455","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2015-5400","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-2569","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-2570","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-2571","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-2572","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-3947","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-3948","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-4051","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-4052","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-4053","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-4054","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-4553","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-4554","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-4555","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-4556","tags":["web"]},{"url":"https://www.suse.com/support/update/announcement/2016/suse-su-20162089-1/","tags":["advisory"]},{"url":"https://bugzilla.suse.com/895773","tags":["report"]},{"url":"https://bugzilla.suse.com/967011","tags":["report"]},{"url":"https://bugzilla.suse.com/976708","tags":["report"]},{"url":"https://bugzilla.suse.com/993299","tags":["report"]},{"url":"https://www.suse.com/security/cve/CVE-2011-3205","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2011-4096","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2012-5643","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2013-0188","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2013-4115","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2014-0128","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2014-6270","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2014-7141","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2014-7142","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2016-2390","tags":["web"]},{"url":"https://ubuntu.com/security/CVE-2015-5400","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2015-5400","tags":["report"]},{"url":"","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2015-5400","description":"Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with cache_peer, which allows remote attackers to bypass intended restrictions and gain access to a backend proxy via a CONNECT request.","status":"published","published":"2015-09-28T20:00:00Z","modified":"2024-08-06T06:50:02.095Z","updated_at":"2026-11-02T14:35:39.846011Z"}],"euvd":[{"id":"EUVD-2015-5356","description":"Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with cache_peer, which allows remote attackers to bypass intended restrictions and gain access to a backend proxy via a CONNECT request.","status":"published","published":"2015-09-28T20:00:00Z","modified":"2024-08-06T06:50:02Z","updated_at":"2026-11-03T02:22:00.305488Z"}],"ghsa":[{"id":"GHSA-9pj4-fqm8-w5x7","title":"Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with...","description":"Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with cache_peer, which allows remote attackers to bypass intended restrictions and gain access to a backend proxy via a CONNECT request.","status":"published","published":"2022-05-17T00:48:30Z","modified":"2023-02-03T05:02:36Z","updated_at":"2026-11-02T14:53:12.235581Z"}],"nvd":[{"id":"CVE-2015-5400","description":"Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with cache_peer, which allows remote attackers to bypass intended restrictions and gain access to a backend proxy via a CONNECT request.","status":"published","published":"2015-09-28T20:59:03.28Z","modified":"2026-06-17T00:29:04.243Z","cvss":[{"version":"2.0","score":6.8,"vector":"AV:N/AC:M/Au:N/C:P/I:P/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-264"],"updated_at":"2026-11-02T14:03:09.92183Z"}],"osv":[{"id":"CVE-2015-5400","description":"Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with cache_peer, which allows remote attackers to bypass intended restrictions and gain access to a backend proxy via a CONNECT request.","status":"published","published":"2015-09-28T20:59:03Z","modified":"2026-04-16T06:21:59.489207637Z","updated_at":"2026-11-02T15:44:00.594921Z"},{"id":"DEBIAN-CVE-2015-5400","description":"Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with cache_peer, which allows remote attackers to bypass intended restrictions and gain access to a backend proxy via a CONNECT request.","status":"published","published":"2015-09-28T20:59:03.28Z","modified":"2026-09-09T06:47:25.095240415Z","updated_at":"2026-11-02T15:45:26.752992Z"},{"id":"DLA-286-1","title":"squid3 - security update","status":"published","published":"2015-07-30T00:00:00Z","modified":"2026-03-09T01:21:44.653621Z","updated_at":"2026-11-02T15:46:11.189256Z"},{"id":"DSA-3327-1","title":"squid3 - security update","status":"published","published":"2015-08-03T00:00:00Z","modified":"2026-03-09T01:19:33.993898Z","updated_at":"2026-11-02T15:46:16.199525Z"},{"id":"MGASA-2015-0347","title":"Updated squid packages fix CVE-2015-5400","description":"Updated squid packages fix security vulnerability:\n\nAlex Rousskov discovered that Squid configured with cache_peer and operating\non explicit proxy traffic does not correctly handle CONNECT method peer\nresponses. In some configurations, it allows remote clients to bypass security\nin an explicit gateway proxy (CVE-2015-5400).\n","status":"published","published":"2015-09-08T17:55:59Z","modified":"2026-04-16T06:23:41.636162113Z","updated_at":"2026-11-02T15:49:39.792687Z"},{"id":"openSUSE-SU-2024:10307-1","title":"squid-3.5.22-1.1 on GA media","description":"These are all security issues fixed in the squid-3.5.22-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2024-06-15T00:00:00Z","modified":"2026-02-04T02:29:53.823463Z","updated_at":"2026-11-02T16:58:33.135986Z"},{"id":"SUSE-SU-2016:2008-1","title":"Security update for squid","description":"\nThe Squid HTTP proxy has been updated to version 3.3.14, fixing the following\nsecurity issues:\n\n- Fixed multiple Denial of Service issues in HTTP Response processing.\n  (CVE-2016-2569, CVE-2016-2570, CVE-2016-2571, CVE-2016-2572,\n   bsc#968392, bsc#968393, bsc#968394, bsc#968395)\n- CVE-2016-3947: Buffer overrun issue in pinger ICMPv6\n  processing. (bsc#973782)\n- CVE-2015-5400: Improper protection of alternate path. (bsc#938715)\n- CVE-2015-3455: Squid http proxy configured with client-first SSL\n  bumping did not correctly validate server certificate. (bsc#929493)\n- CVE-2016-3948: Fixed denial of service in HTTP Response processing\n  (bsc#973783)\n- CVE-2016-4051: fixes buffer overflow in cachemgr.cgi (bsc#976553)\n- CVE-2016-4052, CVE-2016-4053, CVE-2016-4054: Fixed multiple issues in\n  ESI processing (bsc#976556)\n- CVE-2016-4553: Fixed cache poisoning issue in HTTP Request handling (bsc#979009)\n- CVE-2016-4554: Fixed header smuggling issue in HTTP Request processing\n  (bsc#979010)\n- Fixed multiple Denial of Service issues in ESI Response processing.\n  (CVE-2016-4555, CVE-2016-4556, bsc#979011, bsc#979008)\n\nAdditionally, the following non-security issues have been fixed:\n\n- Fix header size in script unsquid.pl. (bsc#902197)\n- Add external helper ext_session_acl to package. (bsc#959290)\n- Update forward_max_tries to permit 25 server paths\n  With cloud sites becoming more popular more CDN servers are producing\n  long lists of IPv6 and IPv4 addresses. If there are not enough paths\n  selected the IPv4 ones may never be reached.\n- squid.init: wait that squid really dies when we kill it on upgrade instead\n  of proclaiming its demise prematurely (bnc#963539)\n","status":"published","published":"2016-08-09T11:32:29Z","modified":"2026-02-04T04:20:47.153034Z","updated_at":"2026-11-02T15:53:43.438985Z"},{"id":"SUSE-SU-2016:2089-1","title":"Security update for squid3","description":"\n\nThis update for squid3 fixes the following issues:\n\n- Multiple issues in pinger ICMP processing.  (CVE-2014-7141, CVE-2014-7142) \n\n- CVE-2016-3947: Buffer overrun issue in pinger\n    ICMPv6 processing. (bsc#973782)\n\n-  CVE-2016-4554: fix header smuggling issue in HTTP Request processing (bsc#979010)\n\n- Fix multiple Denial of Service issues in HTTP Response processing.\n    (CVE-2016-2569, CVE-2016-2570, CVE-2016-2571, CVE-2016-2572,\n     bsc#968392, bsc#968393, bsc#968394, bsc#968395)\n- Regression caused by the DoS fixes above (bsc#993299)\n\n- CVE-2016-3948: Fix denial of service in HTTP Response processing (bsc#973783)\n\n- CVE-2016-4051: fixes buffer overflow in cachemgr.cgi (bsc#976553)\n\n- CVE-2016-4052, CVE-2016-4053, CVE-2016-4054:\n  * fixes multiple issues in ESI processing (bsc#976556)\n\n- CVE-2016-4556: fixes double free vulnerability in Esi.cc (bsc#979008)\n\n- CVE-2015-5400: Improper Protection of Alternate Path (bsc#938715)\n\n- CVE-2014-6270: fix off-by-one in snmp subsystem (bsc#895773)\n\n- Memory leak in squid3 when using external_acl (bsc#976708)\n","status":"published","published":"2016-08-16T12:56:03Z","modified":"2026-02-04T03:13:42.545823Z","updated_at":"2026-11-02T15:53:43.438985Z"},{"id":"UBUNTU-CVE-2015-5400","description":"Squid before 3.5.6 does not properly handle CONNECT method peer responses when configured with cache_peer, which allows remote attackers to bypass intended restrictions and gain access to a backend proxy via a CONNECT request.","status":"published","published":"2015-09-28T20:59:00Z","modified":"2025-09-08T16:43:26Z","updated_at":"2026-11-02T15:54:10.385269Z"}]}}