CVE-2026-55893

Name	CVE-2026-55893
Description	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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
capstone (PTS)	bullseye	4.0.2-3	vulnerable
	bookworm	4.0.2-5	vulnerable
	trixie	5.0.7-1~deb13u1	vulnerable
	forky, sid	5.0.9-1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
capstone	source	(unstable)	(unfixed)

Notes

https://github.com/capstone-engine/capstone/security/advisories/GHSA-3hpv-wr3j-rxwh
https://github.com/capstone-engine/capstone/pull/2968
Fixed by: https://github.com/capstone-engine/capstone/commit/09e76802380b9e94d9720c44458d9d5282219e7e (6.0.0-Alpha10)
https://github.com/capstone-engine/capstone/pull/2969
Fixed by: https://github.com/capstone-engine/capstone/commit/e17ee44a8307ea33375b4727ac4f987650bf7bed (v5 branch)