An issue was discovered in OpenWrt 18.06.0 to 18.06.6 and 19.07.0, and LEDE 17.01.0 to 17.01.7. A bug in the fork of the opkg package manager before 2020-01-25 prevents correct parsing of embedded checksums in the signed repository index, allowing a man-in-the-middle attacker to inject arbitrary package payloads (which are installed without verification).
libubox in OpenWrt before 18.06.7 and 19.x before 19.07.1 has a tagged binary data JSON serialization vulnerability that may cause a stack based buffer overflow.
uhttpd in OpenWrt through 18.06.5 and 19.x through 19.07.0-rc2 has an integer signedness error. This leads to out-of-bounds access to a heap buffer and a subsequent crash. It can be triggered with an HTTP POST request to a CGI script, specifying both "Transfer-Encoding: chunked" and a large negative Content-Length value.