The URL percent-encoding decode function in libcurl is called `curl_easy_unescape`. Internally, even if this function would be made to allocate a unscape destination buffer larger than 2GB, it would return that new length in a signed 32 bit integer variable, thus the length would get either just truncated or both truncated and turned negative. That could then lead to libcurl writing outside of its heap based buffer. This can be triggered by a user on a 64bit system if the user can send in a custom (very large) URL to a libcurl using program. External References: https://curl.haxx.se/docs/adv_20161102H.html
Created attachment 1213778 [details] Upstream patch
Created curl tracking bugs for this issue: Affects: fedora-all [bug 1390894]
Created mingw-curl tracking bugs for this issue: Affects: fedora-all [bug 1390895] Affects: epel-7 [bug 1390896]
This issue has been addressed in the following products: Red Hat JBoss Core Services Via RHSA-2018:2486 https://access.redhat.com/errata/RHSA-2018:2486
This issue has been addressed in the following products: Red Hat Software Collections for Red Hat Enterprise Linux 6 Red Hat Software Collections for Red Hat Enterprise Linux 7 Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUS Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUS Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUS Via RHSA-2018:3558 https://access.redhat.com/errata/RHSA-2018:3558