How severe is CVE-2013-6422?

CVE-2013-6422 has a CVSS 2.0 base score of 4.0, rated medium severity.

Is CVE-2013-6422 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2013-6422?

CVE-2013-6422 primarily affects Haxx Libcurl. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2013-6422?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2013-6422 published?

CVE-2013-6422 was published on 2013-12-23 and last updated on 2026-06-17.

CVE-2013-6422

CVE-2013-6422 is a medium-severity vulnerability in Haxx Libcurl with a CVSS 2.0 base score of 4.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: Medium (CVSS 2.0 base score 4.0)
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Haxx Libcurl
Published: 2013-12-23
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2013-6422?: CVE-2013-6422 has a CVSS 2.0 base score of 4.0, rated medium severity.
Is CVE-2013-6422 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2013-6422?: CVE-2013-6422 primarily affects Haxx Libcurl. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2013-6422?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2013-6422 published?: CVE-2013-6422 was published on 2013-12-23 and last updated on 2026-06-17.

References

Affected products (23)

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

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