Bug 2521129 - CVE-2025-67873 ruby: Capstone: Heap buffer overflow via skipdata callback allows denial of service or arbitrary code execution. [fedora-43]
Summary: CVE-2025-67873 ruby: Capstone: Heap buffer overflow via skipdata callback all...
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Fedora
Classification: Fedora
Component: ruby
Version: 43
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Vít Ondruch
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["90e919ed-5d1b-42ff-b8d6-6...
Depends On:
Blocks: CVE-2025-67873
TreeView+ depends on / blocked
 
Reported: 2026-08-21 19:29 UTC by Praise Ogwuche
Modified: 2026-08-24 10:00 UTC (History)
5 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2026-08-24 10:00:07 UTC
Type: ---
Embargoed:

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Description Praise Ogwuche 2026-08-21 19:29:10 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Capstone is a disassembly framework. In versions 6.0.0-Alpha5 and prior, Skipdata length is not bounds-checked, so a user-provided skipdata callback can make cs_disasm/cs_disasm_iter memcpy more than 24 bytes into cs_insn.bytes, causing a heap buffer overflow in the disassembly path. Commit cbef767ab33b82166d263895f24084b75b316df3 fixes the issue.
Comment 1 Vít Ondruch 2026-08-24 10:00:07 UTC 
Capstone is an optional Rust dependency used only behind the disasm Cargo feature in YJIT/ZJIT. This feature is not enabled in Fedora Ruby builds and capstone is not built, linked, or shipped.

Ref :
https://github.com/ruby/ruby/blob/09fdc3bed9bd0bff37c7a56ef38964654a599e87/yjit/Cargo.toml#L15
https://github.com/ruby/ruby/blob/09fdc3bed9bd0bff37c7a56ef38964654a599e87/yjit/src/disasm.rs#L162-L216
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