CVE-2026-28525: Swupdate

Medium severity, CVSS 6.8. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• Swupdate Swupdate: up to and including 2025.12

Published 2026-04-23. Last modified 2026-07-14.