CVE catalog

CVE-2026-49263

Capstone is a disassembly framework. Prior to version…

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.

Severity: Medium · CVSS 6.8CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Published: Aug 14, 2026, 5:49:36 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.17% · Oct 27, 2026

Projects and upstream resources

[capstone][Source-reported homepage]

Reported versions and fixes

Each observation applies to its named package, distribution, and release. Distribution backports can fix a vulnerability while retaining an older upstream version number.

Version impact has not been established. The original provider fields are retained below.

Provider details and historical evidence

Original provider fields

{
  "package_releases": [
    {
      "name": "capstone",
      "status": "vulnerable",
      "release": "sid",
      "version": "5.0.9-1"
    },
    {
      "name": "capstone",
      "status": "vulnerable",
      "release": "forky",
      "version": "5.0.9-1"
    },
    {
      "name": "capstone",
      "status": "vulnerable",
      "release": "trixie",
      "version": "5.0.7-1~deb13u1"
    },
    {
      "name": "capstone",
      "status": "vulnerable",
      "release": "bookworm",
      "version": "4.0.2-5"
    }
  ],
  "fixed_versions": [
    {
      "bug": 1144519,
      "name": "capstone",
      "type": "source",
      "origin": null,
      "release": "sid",
      "urgency": "not yet assigned",
      "fixed_version": ""
    },
    {
      "bug": 1144519,
      "name": "capstone",
      "type": "source",
      "origin": null,
      "release": "forky",
      "urgency": "not yet assigned",
      "fixed_version": ""
    },
    {
      "bug": 1144519,
      "name": "capstone",
      "type": "source",
      "origin": null,
      "release": "trixie",
      "urgency": "not yet assigned",
      "fixed_version": ""
    },
    {
      "bug": 1144519,
      "name": "capstone",
      "type": "source",
      "origin": null,
      "release": "bookworm",
      "urgency": "not yet assigned",
      "fixed_version": ""
    }
  ],
  "distribution_packages": []
}

[Debian bug #1144519]

Publisher notes

[trixie] capstone: Minor issue [bookworm] capstone: Minor issue

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

[capstone-tool]Unknown
Source package: [capstone]
Details (2)
- 4.0.2-5 · amd64 · bookworm
  Affected
  nvd · capstone · debian · bookworm; nvd · capstone · debian · 12
- 4.0.2-5 · arm64 · bookworm
  Affected
  nvd · capstone · debian · bookworm; nvd · capstone · debian · 12
[libcapstone4]Unknown
Source package: [capstone]
Details (2)
- 4.0.2-5 · amd64 · bookworm
  Affected
  nvd · capstone · debian · bookworm; nvd · capstone · debian · 12
- 4.0.2-5 · arm64 · bookworm
  Affected
  nvd · capstone · debian · bookworm; nvd · capstone · debian · 12
[libcapstone-dev]Unknown
Source package: [capstone]
Details (2)
- 4.0.2-5 · amd64 · bookworm
  Affected
  nvd · capstone · debian · bookworm; nvd · capstone · debian · 12
- 4.0.2-5 · arm64 · bookworm
  Affected
  nvd · capstone · debian · bookworm; nvd · capstone · debian · 12
[python3-capstone]Unknown
Source package: [capstone]
Details (2)
- 4.0.2-5 · amd64 · bookworm
  Affected
  nvd · capstone · debian · bookworm; nvd · capstone · debian · 12
- 4.0.2-5 · arm64 · bookworm
  Affected
  nvd · capstone · debian · bookworm; nvd · capstone · debian · 12

[Debian 13 (Trixie)]

[capstone-tool]Unknown
Source package: [capstone]
Details (2)
- 5.0.7-1~deb13u1 · amd64 · trixie
  Affected
  nvd · capstone · debian · 13
- 5.0.7-1~deb13u1 · arm64 · trixie
  Affected
  nvd · capstone · debian · 13
[libcapstone5]Unknown
Source package: [capstone]
Details (2)
- 5.0.7-1~deb13u1 · amd64 · trixie
  Affected
  nvd · capstone · debian · 13
- 5.0.7-1~deb13u1 · arm64 · trixie
  Affected
  nvd · capstone · debian · 13
[libcapstone-dev]Unknown
Source package: [capstone]
Details (2)
- 5.0.7-1~deb13u1 · amd64 · trixie
  Affected
  nvd · capstone · debian · 13
- 5.0.7-1~deb13u1 · arm64 · trixie
  Affected
  nvd · capstone · debian · 13
[python3-capstone]Unknown
Source package: [capstone]
Details (2)
- 5.0.7-1~deb13u1 · amd64 · trixie
  Affected
  nvd · capstone · debian · 13
- 5.0.7-1~deb13u1 · arm64 · trixie
  Affected
  nvd · capstone · debian · 13

Observed: Oct 23, 2026, 9:41:59 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]