CVE-2013-6422

The GnuTLS backend in libcurl 7.21.4 through 7.33.0, when disabling digital signature verification (CURLOPT_SSL_VERIFYPEER), also disables the CURLOPT_SSL_VERIFYHOST check for CN or SAN host name fields, which makes it easier for remote attackers to spoof servers and conduct man-in-the-middle (MITM) attacks.

Published: 2013-12-23 Last update: 2026-04-29 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2013-6422 is rated Low Risk (34/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.34%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2013-6422

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 2025-03-30 1.28% 0.34% -0.93%
2 2025-03-29 0.34% 1.28% +0.93%
3 2025-03-17 — 0.34% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2013-6422

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.0 2.0 MEDIUM
AV:N/AC:H/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:H)
Exploitation requires uncommon or highly specific conditions.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 4.9 4.9 [email protected]

Weakness enumeration for CVE-2013-6422

OS Trackers for CVE-2013-6422

vendor priority summary link
debian not yet assigned CVE-2013-6422 not yet assigned priority: Debian including 1 source packages (curl), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2013-6422
gentoo normal CVE-2013-6422: 1 GLSA(s) (201401-14), 1 atom(s) (net-misc/curl); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2013-6422
redhat low — https://access.redhat.com/security/cve/CVE-2013-6422
ubuntu medium CVE-2013-6422 medium priority: Ubuntu including 1 source packages (curl), 6 status rows across 6 suites (lucid, precise, quantal, raring, saucy, upstream): released 4, not-affected 1, pending 1. https://ubuntu.com/security/CVE-2013-6422

Affected software / configurations for CVE-2013-6422

Vendor Product Version Raw CPE
debian debian_linux 7.0 cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:*
canonical ubuntu_linux 12.04 cpe:2.3:o:canonical:ubuntu_linux:12.04:-:lts:*:*:*:*:*
canonical ubuntu_linux 12.10 cpe:2.3:o:canonical:ubuntu_linux:12.10:*:*:*:*:*:*:*
canonical ubuntu_linux 13.04 cpe:2.3:o:canonical:ubuntu_linux:13.04:*:*:*:*:*:*:*
canonical ubuntu_linux 13.10 cpe:2.3:o:canonical:ubuntu_linux:13.10:*:*:*:*:*:*:*
haxx libcurl 7.21.4 cpe:2.3:a:haxx:libcurl:7.21.4:*:*:*:*:*:*:*
haxx libcurl 7.21.5 cpe:2.3:a:haxx:libcurl:7.21.5:*:*:*:*:*:*:*
haxx libcurl 7.21.6 cpe:2.3:a:haxx:libcurl:7.21.6:*:*:*:*:*:*:*
haxx libcurl 7.21.7 cpe:2.3:a:haxx:libcurl:7.21.7:*:*:*:*:*:*:*
haxx libcurl 7.22.0 cpe:2.3:a:haxx:libcurl:7.22.0:*:*:*:*:*:*:*
haxx libcurl 7.23.0 cpe:2.3:a:haxx:libcurl:7.23.0:*:*:*:*:*:*:*
haxx libcurl 7.23.1 cpe:2.3:a:haxx:libcurl:7.23.1:*:*:*:*:*:*:*
haxx libcurl 7.24.0 cpe:2.3:a:haxx:libcurl:7.24.0:*:*:*:*:*:*:*
haxx libcurl 7.25.0 cpe:2.3:a:haxx:libcurl:7.25.0:*:*:*:*:*:*:*
haxx libcurl 7.26.0 cpe:2.3:a:haxx:libcurl:7.26.0:*:*:*:*:*:*:*
haxx libcurl 7.27.0 cpe:2.3:a:haxx:libcurl:7.27.0:*:*:*:*:*:*:*
haxx libcurl 7.28.0 cpe:2.3:a:haxx:libcurl:7.28.0:*:*:*:*:*:*:*
haxx libcurl 7.28.1 cpe:2.3:a:haxx:libcurl:7.28.1:*:*:*:*:*:*:*
haxx libcurl 7.29.0 cpe:2.3:a:haxx:libcurl:7.29.0:*:*:*:*:*:*:*
haxx libcurl 7.30.0 cpe:2.3:a:haxx:libcurl:7.30.0:*:*:*:*:*:*:*
haxx libcurl 7.31.0 cpe:2.3:a:haxx:libcurl:7.31.0:*:*:*:*:*:*:*
haxx libcurl 7.32.0 cpe:2.3:a:haxx:libcurl:7.32.0:*:*:*:*:*:*:*
haxx libcurl 7.33.0 cpe:2.3:a:haxx:libcurl:7.33.0:*:*:*:*:*:*:*

References for CVE-2013-6422

cvelogic Threat Intelligence