CVE-2026-59691: fix a heap buffer overflow in the rfbsrc RRE, CoRRE and
hextile decoders, which wrote 32-bit pixels into a buffer sized for the
negotiated bits-per-pixel; write through the correct type for 1, 2 and
4 bytespp and reject any other format, and read colour values at the
negotiated width at all seven call sites instead of a fixed four bytes
CVE-2026-59692: fix a stack buffer overflow in the DTLS connection
handler, which printed the peer certificate subject DN into a fixed
2048-byte stack buffer; allocate it from the returned length instead
and bound the read