SOEM: Out-of-bounds memory access (CVE-2026-70388)

SOEM version 2.0.0 and earlier contains an out-of-bounds memory access vulnerability (CVE-2026-70388). The vulnerability exists because the software performs arithmetic on message length values without proper validation, allowing negative or extremely large values to bypass safety checks. This allows a malicious device on the network to send specially crafted messages that cause the master to write data outside allocated memory boundaries.

Impact

Successful exploitation can lead to memory corruption, which may result in a crash of the master service or potentially allow an attacker to execute arbitrary code on the master system.

Recommendation

Update SOEM to a patched version beyond 2.0.0 once available. In the absence of a patch, restrict network access to the master system to trusted devices only to prevent malicious actors from sending crafted network messages.