Capstone is a disassembly framework. Versions prior to 6.0.0-Alpha8 and 5.0.8 have a NULL pointer dereference in `modRMR
Capstone is a disassembly framework. Versions prior to 6.0.0-Alpha8 and 5.0.8 have a NULL pointer dereference in `modRMRequired()` and `decode()` when disassembling 3DNow! opcodes (`0F 0F`) in builds compiled with `-DCAPSTONE_X86_REDUCE`, allowing a remote attacker to crash any application using the reduced X86 Capstone library by supplying a crafted input containing the 4-byte sequence `0F 0F <modrm> <imm8>`. Versions 6.0.0-Alpha8 and 5.0.8 patch the issue.
Affected packages
- capstone— before 5.0.8
Exploit signal
- Known exploited (CISA KEV)
- No
- EPSS score
- 0.40%
- EPSS percentile
- 32.6%
EPSS is the probability a CVE is exploited in the wild; percentile is its rank among all CVEs. This advisory is in the top 33%.
Sources
- https://github.com/capstone-engine/capstone/commit/a0201371719b5aaa91d318ab2898843718f92d1f
- https://github.com/capstone-engine/capstone/commit/fab595205fee206f5c21be6ed8ad2eaf9225f1c7
- https://github.com/capstone-engine/capstone/pull/2924
- https://github.com/capstone-engine/capstone/security/advisories/GHSA-289w-cm54-fgrm
Structured record: https://osv.dev/vulnerability/PYSEC-2026-3544
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