{"id":"CVE-2013-4206","aliases":["DEBIAN-CVE-2013-4206","DSA-2736-1","EUVD-2013-4111","GHSA-h3qw-gcpw-f6mg","MGASA-2013-0242","openSUSE-SU-2024:10399-1"],"status":"published","title":"Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote...","description":"Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code execution via a crafted DSA signature, which is not properly handled when performing certain bit-shifting operations during modular multiplication.","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":"2026-11-09","score":0.02475,"percentile":0.8466,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-119"],"published":"2013-08-09T17:38:37Z","modified":"2026-09-01T20:03:17Z","fixes":[{"ecosystem":"Debian:12","package":"filezilla","fixed_in":["3.7.3-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"filezilla","fixed_in":["3.7.3-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"filezilla","fixed_in":["3.7.3-1"],"sources":["osv"]},{"ecosystem":"Debian:12","package":"putty","fixed_in":["0.63-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"putty","fixed_in":["0.63-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"putty","fixed_in":["0.63-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"filezilla","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.7.3-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"filezilla","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.7.3-1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"filezilla","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.7.3-1"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"putty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.63-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"putty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.63-1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"putty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.63-1"}]}]},{"source":"osv","ecosystem":"Debian:6.0","package":"putty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.60+2010-02-20-1+squeeze2"}]}],"versions":["0.60+2010-02-20-1","0.60+2010-02-20-1+squeeze1"],"bundled":4},{"source":"osv","ecosystem":"Debian:7","package":"putty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.62-9+deb7u1"}]}],"versions":["0.62-9"],"bundled":4},{"source":"osv","ecosystem":"Mageia:2","package":"putty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.63-1.mga2"}]}],"bundled":4},{"source":"osv","ecosystem":"Mageia:2","package":"filezilla","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.7.3-1.mga2"}]}],"bundled":4},{"source":"osv","ecosystem":"Mageia:3","package":"putty","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.63-1.mga3"}]}],"bundled":4},{"source":"osv","ecosystem":"Mageia:3","package":"filezilla","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.7.3-1.mga3"}]}],"bundled":4},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"filezilla","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.23.0.2-1.1"}]}],"bundled":4}],"products":[{"vendor":"putty","product":"putty"},{"vendor":"simon_tatham","product":"putty"}],"references":[{"url":"http://www.openwall.com/lists/oss-security/2013/08/06/11","tags":["mailing-list","x_refsource_MLIST","x_transferred","web"]},{"url":"http://secunia.com/advisories/54533","tags":["third-party-advisory","x_refsource_SECUNIA","x_transferred","advisory"]},{"url":"http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-modmul.html","tags":["x_refsource_CONFIRM","x_transferred","Vendor Advisory","advisory","web"]},{"url":"http://www.debian.org/security/2013/dsa-2736","tags":["vendor-advisory","x_refsource_DEBIAN","x_transferred","advisory"]},{"url":"http://lists.opensuse.org/opensuse-updates/2013-08/msg00035.html","tags":["vendor-advisory","x_refsource_SUSE","x_transferred","web"]},{"url":"http://secunia.com/advisories/54379","tags":["third-party-advisory","x_refsource_SECUNIA","x_transferred","Vendor Advisory","advisory"]},{"url":"http://svn.tartarus.org/sgt/putty/sshbn.c?sortby=date\u0026r1=9977\u0026r2=9976\u0026pathrev=9977","tags":["x_refsource_CONFIRM","x_transferred","Patch","fix"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2013-4206"},{"url":"https://github.com/advisories/GHSA-h3qw-gcpw-f6mg"},{"url":"https://security-tracker.debian.org/tracker/CVE-2013-4206","tags":["advisory"]},{"url":"https://advisories.mageia.org/MGASA-2013-0242.html","tags":["advisory"]},{"url":"https://bugs.mageia.org/show_bug.cgi?id=10925","tags":["report"]},{"url":"http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/vuln-bignum-division-by-zero.html","tags":["web"]},{"url":"http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/private-key-not-wiped.html","tags":["web"]},{"url":"http://www.openwall.com/lists/oss-security/2013/08/06/13","tags":["web"]},{"url":"http://www.search-lab.hu/advisories/secadv-20130722","tags":["advisory"]},{"url":"","tags":["advisory"]},{"url":"https://www.suse.com/security/cve/CVE-2013-4206","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2013-4207","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2013-4208","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2013-4852","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2013-4206","description":"Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code execution via a crafted DSA signature, which is not properly handled when performing certain bit-shifting operations during modular multiplication.","status":"published","published":"2013-08-19T23:00:00Z","modified":"2024-08-06T16:38:01.677Z","updated_at":"2026-11-02T14:34:57.499208Z"}],"euvd":[{"id":"EUVD-2013-4111","description":"Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code execution via a crafted DSA signature, which is not properly handled when performing certain bit-shifting operations during modular multiplication.","status":"published","published":"2013-08-19T23:00:00Z","modified":"2024-08-06T16:38:01Z","updated_at":"2026-11-03T01:56:32.70868Z"}],"ghsa":[{"id":"GHSA-h3qw-gcpw-f6mg","title":"Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote...","description":"Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code execution via a crafted DSA signature, which is not properly handled when performing certain bit-shifting operations during modular multiplication.","status":"published","published":"2022-05-13T01:07:24Z","modified":"2023-02-01T05:03:08Z","cwes":["CWE-119"],"updated_at":"2026-11-02T14:50:01.019018Z"}],"nvd":[{"id":"CVE-2013-4206","description":"Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code execution via a crafted DSA signature, which is not properly handled when performing certain bit-shifting operations during modular multiplication.","status":"published","published":"2013-08-19T23:55:08.723Z","modified":"2026-06-16T23:56:48.847Z","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-119"],"updated_at":"2026-11-02T14:02:35.248411Z"}],"osv":[{"id":"CVE-2013-4206","description":"Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code execution via a crafted DSA signature, which is not properly handled when performing certain bit-shifting operations during modular multiplication.","status":"published","published":"2013-08-19T23:55:08Z","modified":"2026-04-16T06:15:17.119220974Z","updated_at":"2026-11-02T15:43:59.09154Z"},{"id":"DEBIAN-CVE-2013-4206","description":"Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code execution via a crafted DSA signature, which is not properly handled when performing certain bit-shifting operations during modular multiplication.","status":"published","published":"2013-08-19T23:55:08.723Z","modified":"2026-09-01T20:03:17.580572612Z","updated_at":"2026-11-02T15:45:25.514579Z"},{"id":"DSA-2736-1","title":"putty - several","status":"published","published":"2013-08-11T00:00:00Z","modified":"2026-03-09T01:19:11.54204Z","updated_at":"2026-11-02T15:46:15.489951Z"},{"id":"MGASA-2013-0242","title":"Updated putty and filezilla packages fixes security vulnerability","description":"PuTTY versions 0.62 and earlier - as well as all software that\nintegrates   these versions of PuTTY - are vulnerable to an integer\noverflow leading to heap overflow during the SSH handshake before\nauthentication, caused by improper bounds checking of the length\nparameter received from the SSH server. This allows remote attackers\nto cause denial of service, and may have more severe impact on the\noperation of software that uses PuTTY code (CVE-2013-4852).\n\nPuTTY versions 0.62 and earlier - as well as all software that\nintegrates these versions of PuTTY - are vulnerable to a heap-corrupting\nbuffer underrun bug in the modmul function which performs modular\nmultiplication (CVE-2013-4206).\n\nPuTTY versions 0.62 and earlier - as well as all software that\nintegrates these versions of PuTTY - are vulnerable to a buffer overflow\nvulnerability in the calculation of modular inverses when verifying a\nDSA signature (CVE-2013-4207).\n\nPuTTY versions 0.62 and earlier - as well as all software that\nintegrates these versions of PuTTY - are vulnerable to private keys left\nin memory after being used by PuTTY tools (CVE-2013-4208).\n","status":"published","published":"2013-08-09T17:38:37Z","modified":"2026-04-16T06:24:33.138505177Z","updated_at":"2026-11-02T15:49:39.121227Z"},{"id":"openSUSE-SU-2024:10399-1","title":"filezilla-3.23.0.2-1.1 on GA media","description":"These are all security issues fixed in the filezilla-3.23.0.2-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2024-06-15T00:00:00Z","modified":"2026-02-04T03:14:28.376086Z","updated_at":"2026-11-02T16:58:34.487567Z"}]}}