# CVE-2026-26187: lakeFS vulnerable to path traversal in local block adapter allow cross-namespace and sibling directory access

> Authenticated attackers can read and write files outside designated storage boundaries via path traversal in the local block adapter.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 Feb 2026
- **Updated:** 13 Feb 2026
- **Also known as:** GHSA-699m-4v95-rmpm, GO-2026-4494

## What is CVE-2026-26187?

CVE-2026-26187 is a high-severity path traversal vulnerability in treeverse lakeFS, published on 13 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

lakeFS is an open-source tool that transforms object storage into a Git-like repositories. Prior to 1.77.0, the local block adapter (pkg/block/local/adapter.go) allows authenticated users to read and write files outside their designated storage boundaries. The verifyRelPath function used strings.HasPrefix() to verify that requested paths fall within the configured storage directory. This check was insufficient because it validated only the path prefix without requiring a path separator, allowing access to sibling directories with similar names. Also, the adapter verified that resolved paths stayed within the adapter's base path, but did not verify that object identifiers stayed within their designated storage namespace. This allowed attackers to use path traversal sequences in the object identifier to access files in other namespaces. Fixed in version v1.77.0.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-26187?

3 open source packages ship an affected version, including github.com/treeverse/lakefs. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/treeverse/lakefs` | Go | All versions | 1.77.0 |
| `github.com/treeverse/lakefs` | Go | All versions | 1.77.0 |
| `github.com/treeverse/lakefs` | Go | All versions | 1.77.0 |

Products: Lakefs Lakefs.

## How do I fix CVE-2026-26187?

Upgrade github.com/treeverse/lakefs to 1.77.0 or later.

## Is CVE-2026-26187 being exploited?

There is no known exploitation of CVE-2026-26187 in the wild and no public exploit code.

## Other vulnerabilities in treeverse lakeFS

- [CVE-2026-66006](https://insights.sbomify.com/CVE-2026-66006/): lakeFS Unauthenticated Operator Metadata Overwrite via setup_comm_prefs (medium 6.9)
- [CVE-2025-68671](https://insights.sbomify.com/CVE-2025-68671/): lakeFS is Missing Timestamp Validation in S3 Gateway Authentication (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-26187 and fix it if it is affected.

What it is: CVE-2026-26187 is a high-severity path traversal vulnerability in treeverse lakeFS, published on 13 Feb 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-26187 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/treeverse/lakefs (Go): affected all versions; fixed in 1.77.0
- github.com/treeverse/lakefs (Go): affected all versions; fixed in 1.77.0
- github.com/treeverse/lakefs (Go): affected all versions; fixed in 1.77.0

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-2026-26187/ (Markdown: https://insights.sbomify.com/CVE-2026-26187/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-26187
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-26187
- OSV: https://osv.dev/vulnerability/CVE-2026-26187

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-26187/
Summaries are generated and may contain mistakes; the official description above is the record.