{"id":"UBUNTU-CVE-2026-55893","details":"Capstone is a disassembly framework. In 6.0.0-Alpha9 and earlier, Capstone's arch/SH/SHDisassembler.c SH floating-point decoders such as opFADD, opFMUL, and opFSUB call set_reg() and set_reg_n() using sh_info.op.op_count without checking the fixed-size operands[] array. Repeated crafted instructions processed through cs_disasm_iter() or cs_disasm() with CS_ARCH_SH, CS_MODE_SH2A or CS_MODE_SH4A, CS_MODE_SHFPU, and CS_OPT_DETAIL can increment the operand count beyond the 176-byte sh_info allocation and perform a four-byte heap buffer overflow write. The corruption can crash the process and may enable code execution depending on heap layout. This issue is fixed in version 6.0.0-Alpha10.","modified":"2026-09-02T19:35:54.054761947Z","published":"2026-08-20T22:17:00Z","upstream":["CVE-2026-55893"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-55893"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-55893"},{"type":"REPORT","url":"https://github.com/capstone-engine/capstone/security/advisories/GHSA-3hpv-wr3j-rxwh"},{"type":"REPORT","url":"https://github.com/capstone-engine/capstone/pull/2968"},{"type":"REPORT","url":"https://github.com/capstone-engine/capstone/pull/2969"}],"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_name":"libcapstone3","binary_version":"3.0.4-0.2"},{"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-2026-55893.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-2026-55893.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_version":"4.0.1+really+3.0.5-1build1","binary_name":"libcapstone3"},{"binary_name":"python-capstone","binary_version":"4.0.1+really+3.0.5-1build1"},{"binary_version":"4.0.1+really+3.0.5-1build1","binary_name":"python3-capstone"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55893.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_name":"python3-capstone","binary_version":"4.0.2-5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55893.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_version":"4.0.2-5.1build1","binary_name":"python3-capstone"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55893.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_name":"capstone-tool","binary_version":"5.0.7-2"},{"binary_name":"libcapstone5","binary_version":"5.0.7-2"},{"binary_name":"python3-capstone","binary_version":"5.0.7-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55893.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}