ESB-2018.1163 - [Win][UNIX/Linux][BSD][FreeBSD] nghttp2: Denial of service - Remote/unauthenticated 2018-04-16

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             Denial of service due to NULL pointer dereference
                               16 April 2018


        AusCERT Security Bulletin Summary

Product:           nghttp2
Publisher:         FreeBSD
Operating System:  FreeBSD
                   BSD variants
                   UNIX variants (UNIX, Linux, OSX)
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2018-1000168  

Original Bulletin:

Comment: This advisory references vulnerabilities in products which run on 
         platforms other than FreeBSD. It is recommended that administrators
         running nghttp2 check for an updated version of the software for 
         their operating system.

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nghttp2 -- Denial of service due to NULL pointer dereference

Affected packages
1.10.0 <= libnghttp2 < 1.31.1
1.10.0 <= nghttp2    < 1.31.1


VuXML ID  1fccb25e-8451-438c-a2b9-6a021e4d7a31
Discovery 2018-04-04
Entry     2018-04-13

nghttp2 blog:

    If ALTSVC frame is received by libnghttp2 and it is larger than it can
    accept, the pointer field which points to ALTSVC frame payload is left
    NULL. Later libnghttp2 attempts to access another field through the
    pointer, and gets segmentation fault.

    ALTSVC frame is defined by RFC 7838.

    The largest frame size libnghttp2 accept is by default 16384 bytes.

    Receiving ALTSVC frame is disabled by default. Application has to enable it
    explicitly by calling nghttp2_option_set_builtin_recv_extension_type(opt,

    Transmission of ALTSVC is always enabled, and it does not cause this

    ALTSVC frame is expected to be sent by server, and received by client as
    defined in RFC 7838.

    Client and server are both affected by this vulnerability if the reception
    of ALTSVC frame is enabled. As written earlier, it is useless to enable
    reception of ALTSVC frame on server side. So, server is generally safe
    unless application accidentally enabled the reception of ALTSVC frame.


CVE Name CVE-2018-1000168

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Copyright (C) 2003-2005 Jacques Vidrine and contributors.
Please see the source of this document for full copyright information.

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