CVE-2026-68907

libIEC61850 is an open-source implementation of IEC 61850 client and server protocols including MMS, GOOSE, Sampled Values, and R-Session. Prior to 1.6.2, checkDataSetAccess reverses the source and destination arguments to StringUtils_copyStringToBuffer while constructing an MMS_ASSOCIATION_SPECIFIC dataset reference. The helper treats uninitialized dataSetRef[130] storage as a source string, causing strlen to read beyond the stack buffer, and then copies those bytes into the caller-owned listName buffer. A remote defineNamedVariableList request can crash servers that have dynamic dataset service enabled and a dataset access handler installed; the advisory also observes caller stack corruption but establishes denial of service as the primary impact. This issue is fixed in version 1.6.2.