CVE-2015-2721

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    CVE-2015-2721

    Published: 6 Jul 2015Last Modified: 16 Apr 2026

    Summary:

    Details: Mozilla Network Security Services (NSS) before 3.19, as used in Mozilla Firefox before 39.0, Firefox ESR 31.x before 31.8 and 38.x before 38.1, Thunderbird before 38.1, and other products, does not properly determine state transitions for the TLS state machine, which allows man-in-the-middle attackers to defeat cryptographic protection mechanisms by blocking messages, as demonstrated by removing a forward-secrecy property by blocking a ServerKeyExchange message, aka a "SMACK SKIP-TLS" issue.

    References: http://lists.opensuse.org/opensuse-security-announce/2015-07/msg00033.html, http://lists.opensuse.org/opensuse-security-announce/2015-07/msg00034.html, http://rhn.redhat.com/errata/RHSA-2015-1185.html, http://rhn.redhat.com/errata/RHSA-2015-1664.html, http://www.debian.org/security/2015/dsa-3324, http://www.debian.org/security/2015/dsa-3336, http://www.mozilla.org/security/announce/2015/mfsa2015-71.html, http://www.oracle.com/technetwork/security-advisory/cpuapr2016v3-2985753.html, http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html, http://www.oracle.com/technetwork/topics/security/bulletinapr2016-2952098.html, http://www.oracle.com/technetwork/topics/security/bulletinoct2015-2511968.html, http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html, http://www.securityfocus.com/bid/91787, http://www.ubuntu.com/usn/USN-2656-1, http://www.ubuntu.com/usn/USN-2656-2, http://www.ubuntu.com/usn/USN-2672-1, http://www.ubuntu.com/usn/USN-2673-1, https://bugzilla.mozilla.org/show_bug.cgi?id=1086145, https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.19_release_notes, https://security.gentoo.org/glsa/201512-10, https://security.gentoo.org/glsa/201701-46, https://smacktls.com, https://bugzilla.mozilla.org/show_bug.cgi?id=1086145, https://bugzilla.mozilla.org/show_bug.cgi?id=1086145, http://lists.opensuse.org/opensuse-security-announce/2015-07/msg00025.html, http://lists.opensuse.org/opensuse-security-announce/2015-07/msg00031.html, http://lists.opensuse.org/opensuse-security-announce/2015-08/msg00021.html, http://www.securityfocus.com/bid/75541, http://www.securityfocus.com/bid/83398, http://www.securitytracker.com/id/1032783, http://www.securitytracker.com/id/1032784

    Affected packages

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High