CVE-2026-55893 Capstone SH disassembler `set_reg_n` heap buffer overflow via crafted SH2A FPU bytecode
HighCVSS 7.3
EPSS 0.19%
- Published
- Updated
- Exploit status
- No public exploit known
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.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| capstone-engine capstone | = < 6.0.0-Alpha10 | No fix listed |
| redhat/capstone-main(Red Hat:hummingbird:1) | < 5.0.8-0.3.hum1 | 5.0.8-0.3.hum1 |
| redhat/capstone(Red Hat:enterprise_linux:10) | All versions | No fix listed |
| redhat/capstone(Red Hat:enterprise_linux:9) | All versions | No fix listed |
| redhat/openshift/ose-rhel-coreos-9(Red Hat:openshift:4) | All versions | No fix listed |
| redhat/openshift/ose-rhel-coreos-9(Red Hat:openshift:5) | All versions | No fix listed |
| debian/capstone(Debian:12) | All versions | No fix listed |
| debian/capstone(Debian:12) | = 4.0.2-5 | No fix listed |
| debian/capstone(Debian:12) | = 4.0.2-5.1 | No fix listed |
| debian/capstone(Debian:12) | = 5.0-1~exp1 | No fix listed |
| debian/capstone(Debian:12) | = 5.0.1-1~exp1 | No fix listed |
| debian/capstone(Debian:12) | = 5.0.3-1 | No fix listed |
| debian/capstone(Debian:12) | = 5.0.5-1 | No fix listed |
| debian/capstone(Debian:12) | = 5.0.6-1 | No fix listed |
| debian/capstone(Debian:12) | = 5.0.7-1 | No fix listed |
| debian/capstone(Debian:12) | = 5.0.7-1~deb13u1 | No fix listed |
| debian/capstone(Debian:12) | = 5.0.7-2 | No fix listed |
| debian/capstone(Debian:12) | = 5.0.9-1 | No fix listed |
| debian/capstone(Debian:13) | All versions | No fix listed |
| debian/capstone(Debian:13) | = 5.0.6-1 | No fix listed |
| debian/capstone(Debian:13) | = 5.0.7-1 | No fix listed |
| debian/capstone(Debian:13) | = 5.0.7-1~deb13u1 | No fix listed |
| debian/capstone(Debian:13) | = 5.0.7-2 | No fix listed |
| debian/capstone(Debian:13) | = 5.0.9-1 | No fix listed |
| debian/capstone(Debian:14) | All versions | No fix listed |
Show 10 more
| Product | Affected versions | Fixed in |
|---|---|---|
| debian/capstone(Debian:14) | = 5.0.6-1 | No fix listed |
| debian/capstone(Debian:14) | = 5.0.7-1 | No fix listed |
| debian/capstone(Debian:14) | = 5.0.7-1~deb13u1 | No fix listed |
| debian/capstone(Debian:14) | = 5.0.7-2 | No fix listed |
| debian/capstone(Debian:14) | = 5.0.9-1 | No fix listed |
| ubuntu/capstone(Ubuntu:22.04) | All versions | No fix listed |
| ubuntu/capstone(Ubuntu:24.04) | All versions | No fix listed |
| ubuntu/capstone(Ubuntu:26.04) | All versions | No fix listed |
| ubuntu/capstone(Ubuntu:26.10) | All versions | No fix listed |
| azure linux rust(Azure Linux:3.0) | All versions | No fix listed |
References
- MSRC Security Update Guide vendor-advisory
- https://github.com/capstone-engine/capstone/security/advisories/GHSA-3hpv-wr3j-rxwh
- https://github.com/capstone-engine/capstone/pull/2968
- https://github.com/capstone-engine/capstone/pull/2969
- https://github.com/capstone-engine/capstone/commit/09e76802380b9e94d9720c44458d9d5282219e7e
- https://github.com/capstone-engine/capstone/commit/e17ee44a8307ea33375b4727ac4f987650bf7bed
- https://github.com/capstone-engine/capstone/releases/tag/6.0.0-Alpha10
- Red Hat CVE page mitigation vendor-advisory
- RHSA-2026:59419 patch vendor-advisory
- Red Hat Bugzilla 2520815 issue-tracking
- www.cve.org
- nvd.nist.gov
- Debian Security Tracker CVE-2026-55893 vendor-advisory
- Ubuntu CVE tracker vendor-advisory
- bugs.debian.org issue-tracking