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Vulnerability record · CVE-2016-5420 · published 10 August 2016

CVE-2016-5420: Debian linux improper authorization vulnerability

Debian · Debian Linux

curl and libcurl before 7.50.1 do not check the client certificate when choosing the TLS connection to reuse, which might allow remote attackers to hijack the authentication of the connection by leveraging a previously created connection with a different client certificate.

7.5 CVSS 3.0 High EPSS 15% · top 3.5% CWE-285 · Improper authorization
7.5CVSS 3.0 base score, v2 5.0
15%EPSS exploitation probability, 30 days
NoNot in CISA KEV
3Affected product versions listed by NVD
36References
17 Jun 2026Last modified by NVD

Description

curl and libcurl before 7.50.1 do not check the client certificate when choosing the TLS connection to reuse, which might allow remote attackers to hijack the authentication of the connection by leveraging a previously created connection with a different client certificate.

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

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

References

LinkTags
http://lists.opensuse.org/opensuse-updates/2016-09/msg00011.html
http://lists.opensuse.org/opensuse-updates/2016-09/msg00094.html Third Party Advisory
http://rhn.redhat.com/errata/RHSA-2016-2575.html
http://rhn.redhat.com/errata/RHSA-2016-2957.html
http://www.debian.org/security/2016/dsa-3638 Third Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html
http://www.securityfocus.com/bid/92309
http://www.securitytracker.com/id/1036537
http://www.securitytracker.com/id/1036739
http://www.slackware.com/security/viewer.php?l=slackware-security&y=2016&m=slackware-security.563059
http://www.ubuntu.com/usn/USN-3048-1
https://access.redhat.com/errata/RHSA-2018:3558
https://curl.haxx.se/docs/adv_20160803B.html MitigationPatchVendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GLPXQQKURBQFM4XM6645VRP
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K3GQH4V3XAQ5Z53AMQRDEC3
https://security.gentoo.org/glsa/201701-47
https://source.android.com/security/bulletin/2016-12-01.html
https://www.tenable.com/security/tns-2016-18
http://lists.opensuse.org/opensuse-updates/2016-09/msg00011.html
http://lists.opensuse.org/opensuse-updates/2016-09/msg00094.html Third Party Advisory
http://rhn.redhat.com/errata/RHSA-2016-2575.html
http://rhn.redhat.com/errata/RHSA-2016-2957.html
http://www.debian.org/security/2016/dsa-3638 Third Party Advisory
http://www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html
http://www.securityfocus.com/bid/92309
http://www.securitytracker.com/id/1036537
http://www.securitytracker.com/id/1036739
http://www.slackware.com/security/viewer.php?l=slackware-security&y=2016&m=slackware-security.563059
http://www.ubuntu.com/usn/USN-3048-1
https://access.redhat.com/errata/RHSA-2018:3558
https://curl.haxx.se/docs/adv_20160803B.html MitigationPatchVendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GLPXQQKURBQFM4XM6645VRP
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K3GQH4V3XAQ5Z53AMQRDEC3
https://security.gentoo.org/glsa/201701-47
https://source.android.com/security/bulletin/2016-12-01.html
https://www.tenable.com/security/tns-2016-18

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Source: NIST National Vulnerability Database (record CVE-2016-5420), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.