{"id":"UBUNTU-CVE-2026-49263","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.","modified":"2026-08-19T11:05:28Z","published":"2026-08-14T18:17:00Z","upstream":["CVE-2026-49263"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-49263"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-49263"},{"type":"REPORT","url":"https://github.com/capstone-engine/capstone/security/advisories/GHSA-5m9f-vqcm-g5pr"},{"type":"REPORT","url":"https://github.com/capstone-engine/capstone/blob/251c5bb4bc9bb92973e738ae3c5f4ef86f103356/ChangeLog#L102"}],"affected":[{"package":{"name":"capstone","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/capstone?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.0.4-0.1","3.0.4-0.2"],"ecosystem_specific":{"binaries":[{"binary_version":"3.0.4-0.2","binary_name":"libcapstone3"},{"binary_name":"python-capstone","binary_version":"3.0.4-0.2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49263.json"}},{"package":{"name":"capstone","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/capstone?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.0.4-3","3.0.4-5"],"ecosystem_specific":{"binaries":[{"binary_name":"libcapstone3","binary_version":"3.0.4-5"},{"binary_name":"python-capstone","binary_version":"3.0.4-5"},{"binary_name":"python3-capstone","binary_version":"3.0.4-5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49263.json"}},{"package":{"name":"capstone","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/capstone?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.1+really+3.0.5-1","4.0.1+really+3.0.5-1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"capstone-tool","binary_version":"4.0.1+really+3.0.5-1build1"},{"binary_name":"libcapstone3","binary_version":"4.0.1+really+3.0.5-1build1"},{"binary_name":"python-capstone","binary_version":"4.0.1+really+3.0.5-1build1"},{"binary_name":"python3-capstone","binary_version":"4.0.1+really+3.0.5-1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49263.json"}},{"package":{"name":"capstone","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/capstone?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.2-3","4.0.2-3build1","4.0.2-5"],"ecosystem_specific":{"binaries":[{"binary_name":"capstone-tool","binary_version":"4.0.2-5"},{"binary_version":"4.0.2-5","binary_name":"libcapstone4"},{"binary_version":"4.0.2-5","binary_name":"python3-capstone"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49263.json"}},{"package":{"name":"capstone","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/capstone?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.2-5","4.0.2-5ubuntu1","4.0.2-5.1","4.0.2-5.1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"capstone-tool","binary_version":"4.0.2-5.1build1"},{"binary_version":"4.0.2-5.1build1","binary_name":"libcapstone4"},{"binary_name":"python3-capstone","binary_version":"4.0.2-5.1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-49263.json"}},{"package":{"name":"capstone","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/capstone?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.0.6-1","5.0.6-1build1","5.0.7-2"],"ecosystem_specific":{"binaries":[{"binary_version":"5.0.7-2","binary_name":"capstone-tool"},{"binary_name":"libcapstone5","binary_version":"5.0.7-2"},{"binary_version":"5.0.7-2","binary_name":"python3-capstone"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-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"},{"type":"Ubuntu","score":"medium"}]}