The libcurl API function called `curl_maprintf()` can be tricked into doing a double-free due to an unsafe `size_t` multiplication, on systems using 32 bit `size_t` variables. The function is also used internallty in numerous situations. The function doubles an allocated memory area with realloc() and allows the size to wrap and become zero and when doing so realloc() returns NULL *and* frees the memory - in contrary to normal realloc() fails where it only returns NULL - causing libcurl to free the memory *again* in the error path. Systems with 64 bit versions of the `size_t` type are not affected by this issue. This behavior is triggable using the publicly exposed function. External References: https://curl.haxx.se/docs/adv_20161102D.html
Created attachment 1213773 [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