CVE-2026-77710

A vulnerability in misp-stix could allow a crafted STIX document to influence security-sensitive MISP attribute metadata during import. The STIX import logic automatically selected between the internal MISP parser and the external STIX parser based on metadata contained in the STIX document itself. For STIX2, the presence of MISP-specific tool labels could cause a document to be classified as originating from MISP; similarly, STIX1 relied on the document title. These classification indicators are fully controlled by the STIX producer and therefore cannot constitute a trusted indication of the document's origin. The accompanying fix explicitly notes that the parser choice was previously based solely on labels or header titles that any producer could write, and introduces an explicit classification parameter allowing callers to override this detection. When STIX2 content was handled as an internal MISP export, attributes contained in an x-misp-object were converted by copying the complete x_misp_attributes dictionary and passing it directly to misp_object.add_attribute(). Consequently, a crafted STIX bundle could supply fields that were not part of the expected STIX-to-MISP round-tri