{"id":"CVE-2026-49263","summary":"Capstone WASM `br_table` instruction-size truncation can cause no-progress disassembly and parser desynchronization","details":"Capstone is a disassembly framework. Prior to version 6.0.0-Alpha9, Capstone's WebAssembly backend accepts attacker-controlled raw WASM instruction bytes through the public `cs_disasm()` and `cs_disasm_iter()` APIs. For a large but well-formed `br_table` instruction, the WASM decoder accumulates the immediate length in a wider local variable but returns it through a `uint16_t` instruction-size path. When the encoded instruction length is exactly 65,536 bytes, the size wraps to zero and `cs_disasm()` can repeatedly decode the same instruction without advancing. For larger lengths, `cs_disasm_iter()` advances into the middle of the `br_table` payload and decodes target bytes as subsequent instructions. This is an availability and parser-integrity issue. Version 6.0.0-Alpha9 patches the issue.","aliases":["GHSA-5m9f-vqcm-g5pr"],"modified":"2026-08-16T03:48:30.530597089Z","published":"2026-08-14T17:49:36.804Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49263.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-197"]},"references":[{"type":"WEB","url":"https://github.com/capstone-engine/capstone/blob/251c5bb4bc9bb92973e738ae3c5f4ef86f103356/ChangeLog#L102"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49263.json"},{"type":"ADVISORY","url":"https://github.com/capstone-engine/capstone/security/advisories/GHSA-5m9f-vqcm-g5pr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-49263"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/capstone-engine/capstone","events":[{"introduced":"0"},{"fixed":"973b9096dd82c4efb4d7ba3d95a0e2b73243d3ba"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"6.0.0-Alpha9"}],"source":"AFFECTED_FIELD"}}],"versions":["6.0.0-Alpha8","6.0.0-Alpha7","6.0.0-Alpha6","6.0.0-Alpha5","6.0.0-Alpha4","6.0.0-Alpha3","4.0-alpha2","4.0-alpha1","3.0-rc3","3.0-rc2","3.0-rc1","2.1","2.0","2.0-rc1","1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-49263.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N"}]}