Bug 2523314 - CVE-2026-49263 pe-bear: Capstone: Denial of Service and parser desynchronization via WebAssembly `br_table` instruction-size truncation [fedora-all]
Summary: CVE-2026-49263 pe-bear: Capstone: Denial of Service and parser desynchronizat...
Keywords:
Status: NEW
Alias: None
Product: Fedora
Classification: Fedora
Component: pe-bear
Version: rawhide
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: ---
Assignee: Vitaly
QA Contact:
URL:
Whiteboard: {"flaws": ["a0c2fc9f-468a-4e70-9549-9...
Depends On:
Blocks: CVE-2026-49263
TreeView+ depends on / blocked
 
Reported: 2026-08-25 09:24 UTC by gkamathe
Modified: 2026-08-25 09:24 UTC (History)
1 user (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: ---
Embargoed:


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Description gkamathe 2026-08-25 09:24:52 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. Prior to version 6.0.0-Alpha9, Capstone's WebAssembly backend accepts attacker-controlled raw WASM instruction bytes through the public `cs_disasm()` and `cs_disasm_iter()` APIs. For a large but well-formed `br_table` instruction, the WASM decoder accumulates the immediate length in a wider local variable but returns it through a `uint16_t` instruction-size path. When the encoded instruction length is exactly 65,536 bytes, the size wraps to zero and `cs_disasm()` can repeatedly decode the same instruction without advancing. For larger lengths, `cs_disasm_iter()` advances into the middle of the `br_table` payload and decodes target bytes as subsequent instructions. This is an availability and parser-integrity issue. Version 6.0.0-Alpha9 patches the issue.


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