# CVE-2020-29529: Unsafe tar unpacking in HashiCorp go-slug

> Attackers can bypass directory traversal protections in go-slug using multiple symlinks to read or modify files outside the intended directory.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Dec 2020
- **Updated:** 4 Aug 2024
- **Also known as:** DEBIAN-CVE-2020-29529, GHSA-2g5j-5x95-r6hr, GO-2021-0094

## What is CVE-2020-29529?

CVE-2020-29529 is a high-severity path traversal vulnerability in n/a, published on 3 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

HashiCorp go-slug up to 0.4.3 did not fully protect against directory traversal while unpacking tar archives, and protections could be bypassed with specific constructions of multiple symlinks. Fixed in 0.5.0.

Weakness: CWE-59 (Improper Link Resolution Before File Access), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2020-29529?

3 open source packages ship an affected version, including github.com/hashicorp/go-slug. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/hashicorp/go-slug` | Go | All versions | 0.5.0 |
| `github.com/hashicorp/go-slug` | Go | All versions | 0.5.0 |
| `github.com/hashicorp/go-slug` | Go | All versions | 0.5.0 |

Products: Hashicorp Go-Slug.

## How do I fix CVE-2020-29529?

Upgrade github.com/hashicorp/go-slug to 0.5.0 or later.

## Is CVE-2020-29529 being exploited?

There is no known exploitation of CVE-2020-29529 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2025-0377](https://insights.sbomify.com/CVE-2025-0377/): HashiCorp go-slug Vulnerable to Zip Slip Attack (high 7.5)
- [CVE-2026-14978](https://insights.sbomify.com/CVE-2026-14978/): Unicode normalization mismatch in go-slug ignore pattern matching may bypass intended file exclusions (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-29529 and fix it if it is affected.

What it is: CVE-2020-29529 is a high-severity path traversal vulnerability in n/a, published on 3 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-29529 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/hashicorp/go-slug (Go): affected all versions; fixed in 0.5.0
- github.com/hashicorp/go-slug (Go): affected all versions; fixed in 0.5.0
- github.com/hashicorp/go-slug (Go): affected all versions; fixed in 0.5.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2020-29529/ (Markdown: https://insights.sbomify.com/CVE-2020-29529/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-29529
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-29529
- OSV: https://osv.dev/vulnerability/CVE-2020-29529

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-29529/
Summaries are generated and may contain mistakes; the official description above is the record.