An integer overflow or wraparound occurs in the arrayDimensions product calculation used by the UA_Variant type in open62541. The flaw allows a remote attacker to cause the library to read heap memory beyond the bounds of a properly sized array, which can lead to disclosure of sensitive data stored on the heap. The vulnerability stems from improper handling of integer arithmetic, classified as CWE-190.

The affected product is the open62541 OPC UA stack, distributed by o6 Automation. No specific product version range is listed in the advisory, so any release before the fix is considered vulnerable. The security note recommends that users obtain the latest patched version by contacting o6 Automation or by pulling the relevant commits from the GitHub repository. If a user cannot immediately apply a newer release, the stack should be considered at risk.

The CVSS score of 8.7 indicates a high severity vulnerability. The EPSS score of 0.00434 (0.434%) indicates a very low but non-zero exploitation probability, suggesting the flaw is not widely targeted yet. The flaw’s effect—remote read of out-of-bounds heap memory—implies that exploitation is still feasible over the network where the OPC UA stack is exposed, especially if the stack runs with privileged or unrestricted memory access. The advisory does not indicate that the flaw is listed in the CISA KEV catalog, which suggests no widely reported exploits as of the analysis time. The primary attack vector is inferred to be remote, stemming from the network-facing OPC UA service that processes client requests.