SWUpdate through 2026.05.1 contains an improper certificate validation vulnerability in crypto/swupdatecmsverifyopenssl.c that trusts untrusted X.509 certificates embedded in CMS SignedData for chain building. Attackers holding a signing key from a sibling intermediate under the same root can embed that intermediate in the signature to install malicious updates.

SWUpdate contains an integer underflow vulnerability in the multipart upload parser in mongoosemultipart.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 mghttpmultipartcontinuewaitforchunk() 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.

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.