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VulnerabilityPublished Updated

CVE-2026-49263: capstone · Numeric Truncation Error

Affects capstoneSource CVE Database V5

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Not known to be exploited · CVSS 2.0 Low : upgrade to 6.0.0-Alpha9 when convenient.

Data as of 12 Nov 2026, 23:24 UTC

CVSS 4.0 base score
2.0Low
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.0.0-Alpha9
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 14 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

What to do

Upgrade capstone to 6.0.0-Alpha9.

Affected software

ProductAffectedFixed in
capstone-enginecapstoneAffected
  • <6.0.0-Alpha9
Fixed in
  • 6.0.0-Alpha9
GitHubcapstone-engine/capstonepkg:github/capstone-engine/capstoneOther threatsAffected
  • =6.0.0-Alpha9
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Version 6.0.0-Alpha9 of capstone fixes this vulnerability. Users should upgrade to this version or later to remediate the issue. No other mitigation or workaround is indicated.

Description

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.

References

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