{"id":"CVE-2017-17439","url":"https://www.cyber-defence.io/tools/cve/CVE-2017-17439","generatedAt":"2026-10-28T19:45:45.293Z","title":"In Heimdal through 7.4, remote unauthenticated attackers are able to crash the KDC by sending a crafted UDP packet containing empty data fields for client name or realm.","description":"In Heimdal through 7.4, remote unauthenticated attackers are able to crash the KDC by sending a crafted UDP packet containing empty data fields for client name or realm. The parser would unconditionally dereference NULL pointers in that case, leading to a segmentation fault. This is related to the _kdc_as_rep function in kdc/kerberos5.c and the der_length_visible_string function in lib/asn1/der_length.c.","published":"2017-12-06T15:29:00.000Z","lastModified":"2026-06-17T01:10:48.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.0","score":7.5,"severity":"HIGH","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-476"],"affected":["debian/debian linux","heimdal project/heimdal"],"epss":{"score":0.03427,"percentile":0.88859,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (3.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"http://h5l.org/advisories.html?show=2017-12-08","source":"cve@mitre.org"},{"url":"http://www.h5l.org/pipermail/heimdal-announce/2017-December/000008.html","source":"cve@mitre.org"},{"url":"http://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.html","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144","tags":["Issue Tracking","Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/heimdal/heimdal/issues/353","tags":["Patch","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://www.debian.org/security/2017/dsa-4055","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://h5l.org/advisories.html?show=2017-12-08","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.h5l.org/pipermail/heimdal-announce/2017-December/000008.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144","tags":["Issue Tracking","Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/heimdal/heimdal/issues/353","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2017/dsa-4055","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2017-17439","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}