# CVE-2026-66063: goshs has a Path Traversal issue > An unauthenticated attacker can upload files outside the served directory via path traversal in the multipart upload handler. - **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/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:** 28 Jul 2026 - **Updated:** 29 Jul 2026 - **Also known as:** GHSA-wg2q-39h6-66x9, GO-2026-6137 ## What is CVE-2026-66063? CVE-2026-66063 is a medium-severity path traversal vulnerability in goshs-labs goshs, published on 28 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official description goshs is a feature-rich single-binary file server for red teamers and developers. Prior to 2.1.5, the httpserver/updown.go multipart upload handler split part.FileName() on / but did not reject .., allowing an unauthenticated upload with filename .. to create a file outside the served tree. This issue is fixed in version 2.1.5. Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) ## Which versions are affected by CVE-2026-66063? 11 open source packages ship an affected version, including github.com/patrickhener/goshs, github.com/patrickhener/goshs/v2 and goshs.de/goshs. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/patrickhener/goshs` | Go | All versions | None | | `github.com/patrickhener/goshs` | Go | All versions to 1.1.4 | None | | `github.com/patrickhener/goshs` | Go | All versions to 1.1.4 | None | | `github.com/patrickhener/goshs/v2` | Go | All versions | 2.1.5-0.20260727065949-f3ef599e4091 | | `github.com/patrickhener/goshs/v2` | Go | All versions | 2.1.5-0.20260727065949-f3ef599e4091 | | `goshs.de/goshs` | Go | All versions | None | | `goshs.de/goshs` | Go | All versions to 1.1.4 | None | | `goshs.de/goshs` | Go | All versions to 1.1.4 | None | | `goshs.de/goshs/v2` | Go | All versions | 2.1.5-0.20260727065949-f3ef599e4091 | | `goshs.de/goshs/v2` | Go | All versions | 2.1.5-0.20260727065949-f3ef599e4091 | | `goshs.de/goshs/v2` | Go | All versions | 2.1.5-0.20260727065949-f3ef599e4091 | ## How do I fix CVE-2026-66063? Upgrade to a fixed version. ## Is CVE-2026-66063 being exploited? There is no known exploitation of CVE-2026-66063 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-66063 and fix it if it is affected. What it is: CVE-2026-66063 is a medium-severity path traversal vulnerability in goshs-labs goshs, published on 28 Jul 2026. 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-2026-66063 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/patrickhener/goshs (Go): affected all versions; no fix listed - github.com/patrickhener/goshs (Go): affected all versions up to 1.1.4; no fix listed - github.com/patrickhener/goshs (Go): affected all versions up to 1.1.4; no fix listed - github.com/patrickhener/goshs/v2 (Go): affected all versions; fixed in 2.1.5-0.20260727065949-f3ef599e4091 - github.com/patrickhener/goshs/v2 (Go): affected all versions; fixed in 2.1.5-0.20260727065949-f3ef599e4091 - goshs.de/goshs (Go): affected all versions; no fix listed - goshs.de/goshs (Go): affected all versions up to 1.1.4; no fix listed - goshs.de/goshs (Go): affected all versions up to 1.1.4; no fix listed - goshs.de/goshs/v2 (Go): affected all versions; fixed in 2.1.5-0.20260727065949-f3ef599e4091 - goshs.de/goshs/v2 (Go): affected all versions; fixed in 2.1.5-0.20260727065949-f3ef599e4091 - goshs.de/goshs/v2 (Go): affected all versions; fixed in 2.1.5-0.20260727065949-f3ef599e4091 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-2026-66063/ (Markdown: https://insights.sbomify.com/CVE-2026-66063/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-66063 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-66063 - OSV: https://osv.dev/vulnerability/CVE-2026-66063 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-66063/ Summaries are generated and may contain mistakes; the official description above is the record.