CVE-2026-55893
Capstone SH disassembler `set_reg_n` heap buffer overflow via crafted SH2A FPU bytecode
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- None
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.3
Capstone SH disassembler `set_reg_n` heap buffer overflow via crafted SH2A FPU bytecode
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.
- Record
CVE-2026-55893- CVSS 4.0
- 7.3 High
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 - Weakness
- CWE-122
- Updated
- 2026-11-02
EUVDEUVD-2026-63673
7.3
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.
- Record
EUVD-2026-63673- CVSS 4.0
- 7.3 High
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 - Updated
- 2026-11-02
NVD
7.3
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.
- Record
CVE-2026-55893- CVSS 4.0
- 7.3 High
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-122
- Updated
- 2026-11-02
OSV
7.3
Capstone SH disassembler `set_reg_n` heap buffer overflow via crafted SH2A FPU bytecode
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.
- Record
CVE-2026-55893- CVSS 4.0
- 7.3 High
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 - Weakness
- CWE-122
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-55893
7.3
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.
- Record
DEBIAN-CVE-2026-55893- CVSS 4.0
- 7.3 High
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Updated
- 2026-11-02
OSVRHSA-2026:59419
7.0
Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
- Record
RHSA-2026:59419- CVSS 3.1
- 7.0 High
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-55893
7.3
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.
- Record
UBUNTU-CVE-2026-55893- CVSS 4.0
- 7.3 High
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 - Updated
- 2026-11-02
OSVAZL-96894 No score
CVE-2026-55893 affecting package capstone 4.0.2-4
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.
- Record
AZL-96894- Updated
- 2026-11-02
OSVAZL-97416 No score
CVE-2026-55893 affecting package rust for versions less than 1.96.1-1
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.
- Record
AZL-97416- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
capstoneAzure Linux:3 |
through 4.0.2-4 | None known |
rustAzure Linux:3 |
1.85.0 up to 1.96.1-1 | 1.96.1-1 |
capstoneAlpaquita:23 |
4.0.2-r5 and later | None known |
capstoneAlpaquita:25 |
5.0.6-r0 and later | None known |
capstoneAlpaquita:stream |
4.0.2-r5 and later | None known |
capstoneDebian:12 |
All versions, plus listed versions 4.0.2-54.0.2-5.15.0-1~exp15.0.1-1~exp15.0.3-1 Show 6 moreShow less5.0.5-15.0.6-15.0.7-15.0.7-1~deb13u15.0.7-25.0.9-1 |
None known |
capstoneDebian:13 |
All versions, plus listed versions 5.0.6-15.0.7-15.0.7-1~deb13u15.0.7-25.0.9-1 |
None known |
capstoneDebian:14 |
All versions, plus listed versions 5.0.6-15.0.7-15.0.7-1~deb13u15.0.7-25.0.9-1 |
None known |
capstoneRed Hat:hummingbird:1 |
before 0:5.0.8-0.3.hum1 | 0:5.0.8-0.3.hum1 |
capstone-develRed Hat:hummingbird:1 |
before 0:5.0.8-0.3.hum1 | 0:5.0.8-0.3.hum1 |
Show 10 moreShow less
| Package | Affected | Fixed |
|---|---|---|
capstone-javaRed Hat:hummingbird:1 |
before 0:5.0.8-0.3.hum1 | 0:5.0.8-0.3.hum1 |
capstone-staticRed Hat:hummingbird:1 |
before 0:5.0.8-0.3.hum1 | 0:5.0.8-0.3.hum1 |
python3-capstoneRed Hat:hummingbird:1 |
before 0:5.0.8-0.3.hum1 | 0:5.0.8-0.3.hum1 |
capstoneUbuntu:16.04:LTS |
All versions, plus listed versions 3.0.4-0.13.0.4-0.2 |
None known |
capstoneUbuntu:18.04:LTS |
All versions, plus listed versions 3.0.4-33.0.4-5 |
None known |
capstoneUbuntu:20.04:LTS |
All versions, plus listed versions 4.0.1+really+3.0.5-14.0.1+really+3.0.5-1build1 |
None known |
capstoneUbuntu:22.04:LTS |
All versions, plus listed versions 4.0.2-34.0.2-3build14.0.2-5 |
None known |
capstoneUbuntu:24.04:LTS |
All versions, plus listed versions 4.0.2-54.0.2-5ubuntu14.0.2-5.14.0.2-5.1build1 |
None known |
capstoneUbuntu:26.10 |
All versions, plus listed versions 5.0.7-25.0.9-1 |
None known |
capstoneUbuntu:26.04:LTS |
All versions, plus listed versions 5.0.6-15.0.6-1build15.0.7-2 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-55893 is a high vulnerability (CVSS 7.3) in Capstone-engine Capstone, published August 20, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.19%, the 8th percentile. Fixed in rust 1.96.1-1.
References
github.com/capstone-engine/capstone/security/advisories/GHSA-3hpv-wr3j-rxwh
github.com/capstone-engine/capstone/pull/2968
github.com/capstone-engine/capstone/pull/2969
github.com/capstone-engine/capstone/commit/09e76802380b9e94d9720c44458d9d5282219e7e
github.com/capstone-engine/capstone/commit/e17ee44a8307ea33375b4727ac4f987650bf7bed
github.com/capstone-engine/capstone/releases/tag/6.0.0-Alpha10
Show 17 moreShow less
nvd.nist.gov/vuln/detail/CVE-2026-55893
docs.bell-sw.com/security/cves/CVE-2026-55893
github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55893.json
security-tracker.debian.org/tracker/CVE-2026-55893
access.redhat.com/errata/RHSA-2026:59419
access.redhat.com/security/cve/CVE-2026-55893
access.redhat.com/security/cve/CVE-2026-55894
access.redhat.com/security/updates/classification
images.redhat.com
security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_59419.json
bugzilla.redhat.com/show_bug.cgi?id=2520815
cve.org/CVERecord?id=CVE-2026-55893
bugzilla.redhat.com/show_bug.cgi?id=2520820
cve.org/CVERecord?id=CVE-2026-55894
nvd.nist.gov/vuln/detail/CVE-2026-55894
github.com/capstone-engine/capstone/security/advisories/GHSA-gf2c-xwcp-hvf4
ubuntu.com/security/CVE-2026-55893