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Vulnerability record · CVE-2013-6890 · published 23 December 2013

CVE-2013-6890: Debian linux improper authentication vulnerability

Debian · Debian Linux

denyhosts 2.6 uses an incorrect regular expression when analyzing authentication logs, which allows remote attackers to cause a denial of service (incorrect block of IP addresses) via crafted login names.

5.0 CVSS 2.0 Medium EPSS 8.9% · top 4.9% CWE-287 · Improper authentication
5.0CVSS 2.0 base score
8.9%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
8References
17 Jun 2026Last modified by NVD

Description

denyhosts 2.6 uses an incorrect regular expression when analyzing authentication logs, which allows remote attackers to cause a denial of service (incorrect block of IP addresses) via crafted login names.

AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://seclists.org/oss-sec/2013/q4/535
http://secunia.com/advisories/56239 Vendor Advisory
http://www.debian.org/security/2013/dsa-2826
https://bugzilla.redhat.com/show_bug.cgi?id=1045982
http://seclists.org/oss-sec/2013/q4/535
http://secunia.com/advisories/56239 Vendor Advisory
http://www.debian.org/security/2013/dsa-2826
https://bugzilla.redhat.com/show_bug.cgi?id=1045982

Track CVE-2013-6890 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2013-6890), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.