Threats affecting pkg:github/SWUpdate

SWUpdate versions up to and including 2026.05.1 have a critical vulnerability involving improper certificate validation. The flaw occurs in the crypto/swupdate_cms_verify_openssl.c component, where untrusted X.509 certificates embedded in CMS SignedData are trusted during chain building. This allows attackers with a signing key from a sibling intermediate certificate under the same root to embed that intermediate in the signature and potentially install malicious updates.

SWUpdate before 2026.05 is affected by a time-of-check time-of-use (TOCTOU) race condition that allows local unprivileged attackers to escalate privileges to root or install untrusted contents using a signed update.

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.