EXPLOITING INTEGER OVERFLOW IN THE NGINX WEB SERVER: A DEEP DIVE INTO THE VULNERABILITY

Summary from the TLDR InfoSec newsletter

CVE-2017-7529, a now-patched integer overflow in nginx's Range header parser, affected versions 0.5.6 through 1.13.2 and allowed attackers to read out-of-bounds memory from nginx's cache files by crafting two negative byte ranges that caused a signed 64-bit integer overflow in the size accumulator, bypassing the content-length bounds check. When nginx operated as a caching proxy, the exploit leaked the raw cache file contents, including internal request headers, backend server identity, and potentially backend IP addresses. The vulnerability carried limited direct impact but demonstrated how information disclosure primitives can serve as links in a broader attack chain.