# CVE-2026-62843: File Browser: Archive builder turns backslash filenames into path traversal (zip-slip)

> An attacker with upload permissions can create files with backslashes that become path traversal entries in archives, allowing arbitrary file write upon extraction.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 15 Jul 2026
- **Updated:** 15 Jul 2026
- **Also known as:** GHSA-83xp-526h-j3ww, GO-2026-6026

## What is CVE-2026-62843?

CVE-2026-62843 is a medium-severity path traversal vulnerability in filebrowser, published on 15 Jul 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. From 2.63.6 to 2.63.16, File Browser's archive builder uses strings.ReplaceAll(nameInArchive, "\", "/"), which turns a POSIX filename such as ..\..\evil.sh into the archive entry ../../evil.sh, allowing a user with upload permission to plant a backslash-named file that escapes the extraction directory when another user downloads and extracts the generated zip or tar archive. This issue is fixed in version 2.63.17.

Weakness: CWE-23 (Relative Path Traversal), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-62843?

4 open source packages ship an affected version, including github.com/filebrowser/filebrowser/v2 and github.com/filebrowser/filebrowser.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/filebrowser/filebrowser/v2` | Go | From 2.63.6 | 2.63.17 |
| `github.com/filebrowser/filebrowser/v2` | Go | From 2.63.6 | 2.63.17 |
| `github.com/filebrowser/filebrowser/v2` | Go | From 2.63.6 | 2.63.17 |
| `github.com/filebrowser/filebrowser` | Go | All versions | None |

## How do I fix CVE-2026-62843?

Upgrade github.com/filebrowser/filebrowser/v2 to 2.63.17 or later.

## Is CVE-2026-62843 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-62843 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-62843 and fix it if it is affected.

What it is: CVE-2026-62843 is a medium-severity path traversal vulnerability in filebrowser, published on 15 Jul 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-62843 exists.

Affected packages and fixed versions:
- github.com/filebrowser/filebrowser/v2 (Go): affected from 2.63.6; fixed in 2.63.17
- github.com/filebrowser/filebrowser/v2 (Go): affected from 2.63.6; fixed in 2.63.17
- github.com/filebrowser/filebrowser/v2 (Go): affected from 2.63.6; fixed in 2.63.17
- github.com/filebrowser/filebrowser (Go): affected all versions; no fix listed

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-2026-62843/ (Markdown: https://insights.sbomify.com/CVE-2026-62843/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-62843
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-62843
- OSV: https://osv.dev/vulnerability/CVE-2026-62843

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-62843/
Summaries are generated and may contain mistakes; the official description above is the record.