CVE-2026-28525

SWUpdate contains an integer underflow vulnerability in the multipart upload parser in mongoose_multipart.c that allows unauthenticated attackers to cause a denial of service by sending a crafted HTTP POST request to /upload with a malformed multipart boundary and controlled TCP stream timing. Attackers can trigger an integer underflow in the mg_http_multipart_continue_wait_for_chunk() function when the buffer length falls within a specific range, causing an out-of-bounds heap read past the allocated receive buffer to a local IPC socket.

• github.comhttps://github.com/sbabic/swupdate/commit/beee2dc0feef1cfe84f1aa6fc980e104b2e47a74
• www.vulncheck.comhttps://www.vulncheck.com/advisories/swupdate-integer-underflow-in-multipart-upload-parser