libcurl contains a heap buffer overflow in the function (`tftp_receive_packet()`) that recevives data from a TFTP server. It calls `recvfrom()` with the default size for the buffer rather than with the size that was used to allocate it. Thus, the content that might overwrite the heap memory is entirely controlled by the server. Upstream patch: https://curl.haxx.se/0001-tftp-use-the-current-blksize-for-recvfrom.patch References: https://curl.haxx.se/docs/CVE-2019-5436.html
libcurl contains a heap buffer overflow in the function (`tftp_receive_packet()`) that recevives data from a TFTP server. It calls `recvfrom()` with the default size for the buffer rather than with the size that was used to allocate it. Thus, the content that might overwrite the heap memory is entirely controlled by the server. The flaw exists if the user selects to use a "blksize" of 504 or smaller (default is 512). The smaller size that is used, the larger the possible overflow becomes. Users chosing a smaller size than default should be rare as the primary use case for changing the size is to make it larger. It is rare for users to use TFTP across the Internet. It is most commonly used within local networks.
Acknowledgments: Name: the Curl project Upstream: l00p3r
Created curl tracking bugs for this issue: Affects: fedora-all [bug 1712840]
This issue has been addressed in the following products: Red Hat Enterprise Linux 7 Via RHSA-2020:1020 https://access.redhat.com/errata/RHSA-2020:1020
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2019-5436
This issue has been addressed in the following products: Red Hat Enterprise Linux 8 Via RHSA-2020:1792 https://access.redhat.com/errata/RHSA-2020:1792
External References: https://curl.haxx.se/docs/CVE-2019-5436.html
Statement: This flaw exists if the user selects to use a "blksize" of 504 or smaller (default is 512). The smaller size that is used, the larger the possible overflow becomes. Users choosing a smaller size than default should be rare as the primary use case for changing the size is to make it larger. It is rare for users to use TFTP across the Internet. It is most commonly used within local networks.
This issue has been addressed in the following products: Red Hat Enterprise Linux 7.7 Extended Update Support Via RHSA-2020:2505 https://access.redhat.com/errata/RHSA-2020:2505