CVE-2015-6251

Double free vulnerability in GnuTLS before 3.3.17 and 3.4.x before 3.4.4 allows remote attackers to cause a denial of service via a long DistinguishedName (DN) entry in a certificate.

Published: 2015-08-24 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2015-6251 is rated Moderate Risk (58.9/100): CVSS Medium severity, with high exploitation likelihood (EPSS 19.03%, 97th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +12.34% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2015-6251

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 6.69% 19.03% +12.34%
2 2025-07-12 7.08% 6.69% -0.39%
3 2025-06-08 — 7.08% —

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2015-6251

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2015-6251

OS Trackers for CVE-2015-6251

vendor priority summary link
debian not yet assigned CVE-2015-6251 not yet assigned priority: Debian including 1 source packages (gnutls28), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2015-6251
redhat medium — https://access.redhat.com/security/cve/CVE-2015-6251
suse medium — https://www.suse.com/security/cve/CVE-2015-6251/
ubuntu medium CVE-2015-6251 medium priority: Ubuntu including 2 source packages (gnutls26, gnutls28), 24 status rows across 12 suites (artful, bionic, cosmic, disco, precise, trusty, upstream, vivid, wily, xenial, yakkety, zesty): DNE 10, released 9, not-affected 4, needs-triage 1. https://ubuntu.com/security/CVE-2015-6251

NVD evaluator notes for CVE-2015-6251

Comment: <a href="http://cwe.mitre.org/data/definitions/415.html">CWE-415: Double Free</a>

Affected software / configurations for CVE-2015-6251

Vendor Product Version Raw CPE
gnu gnutls 3.3.0 cpe:2.3:a:gnu:gnutls:3.3.0:-:*:*:*:*:*:*
gnu gnutls 3.3.0 cpe:2.3:a:gnu:gnutls:3.3.0:pre0:*:*:*:*:*:*
gnu gnutls 3.3.1 cpe:2.3:a:gnu:gnutls:3.3.1:*:*:*:*:*:*:*
gnu gnutls 3.3.2 cpe:2.3:a:gnu:gnutls:3.3.2:*:*:*:*:*:*:*
gnu gnutls 3.3.3 cpe:2.3:a:gnu:gnutls:3.3.3:*:*:*:*:*:*:*
gnu gnutls 3.3.4 cpe:2.3:a:gnu:gnutls:3.3.4:*:*:*:*:*:*:*
gnu gnutls 3.3.5 cpe:2.3:a:gnu:gnutls:3.3.5:*:*:*:*:*:*:*
gnu gnutls 3.3.6 cpe:2.3:a:gnu:gnutls:3.3.6:*:*:*:*:*:*:*
gnu gnutls 3.3.7 cpe:2.3:a:gnu:gnutls:3.3.7:*:*:*:*:*:*:*
gnu gnutls 3.3.8 cpe:2.3:a:gnu:gnutls:3.3.8:*:*:*:*:*:*:*
gnu gnutls 3.3.9 cpe:2.3:a:gnu:gnutls:3.3.9:*:*:*:*:*:*:*
gnu gnutls 3.3.10 cpe:2.3:a:gnu:gnutls:3.3.10:*:*:*:*:*:*:*
gnu gnutls 3.3.11 cpe:2.3:a:gnu:gnutls:3.3.11:*:*:*:*:*:*:*
gnu gnutls 3.3.12 cpe:2.3:a:gnu:gnutls:3.3.12:*:*:*:*:*:*:*
gnu gnutls 3.3.13 cpe:2.3:a:gnu:gnutls:3.3.13:*:*:*:*:*:*:*
gnu gnutls 3.3.14 cpe:2.3:a:gnu:gnutls:3.3.14:*:*:*:*:*:*:*
gnu gnutls 3.3.15 cpe:2.3:a:gnu:gnutls:3.3.15:*:*:*:*:*:*:*
gnu gnutls 3.3.16 cpe:2.3:a:gnu:gnutls:3.3.16:*:*:*:*:*:*:*
gnu gnutls 3.4.0 cpe:2.3:a:gnu:gnutls:3.4.0:*:*:*:*:*:*:*
gnu gnutls 3.4.1 cpe:2.3:a:gnu:gnutls:3.4.1:*:*:*:*:*:*:*
gnu gnutls 3.4.2 cpe:2.3:a:gnu:gnutls:3.4.2:*:*:*:*:*:*:*
gnu gnutls 3.4.3 cpe:2.3:a:gnu:gnutls:3.4.3:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*

References for CVE-2015-6251

cvelogic Threat Intelligence