Rembg has a Path Traversal via Custom Model Loading

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS

• CVE-2026-40086: 0.59% estimated exploitation activity in the next 30 days; percentile 48.35 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A path traversal vulnerability in the rembg HTTP server allows unauthenticated remote attackers to read arbitrary files from the server's filesystem. By sending a crafted request with a malicious modelpath parameter, an attacker can force the server to attempt loading any file as an ONNX model, revealing file existence, permissions, and potentially file contents through error messages. CWE IDs: CWE-22 (Path Traversal), CWE-73 (External Control of File Name or Path) --- Details Vulnerable Code Flow The vulnerability exists in how the HTTP server handles the extras JSON parameter for custom model types (u2netcustom, discustom, bencustom). 1. Entry Point - rembg/commands/scommand.py The extras parameter is parsed as JSON and passed directly to newsession() without any validation. 2. Path Handling - rembg/sessions/u2netcustom.py The modelpath is returned with tilde expansion but no validation against path traversal. 3. File Read - rembg/sessions/base.py The path is passed to…

Published by the source

10 Apr 2026, 20:00 UTC

Last modified by the source

13 Jul 2026, 07:26 UTC

Source last checked

26 Oct 2026, 13:40 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-3wqj-33cg-xc48

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-3wqj-33cg-xc48

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# Patch Next advisory brief: CVE-2026-40086

Advisory: Rembg has a Path Traversal via Custom Model Loading
IDs: CVE-2026-40086, GHSA-3wqj-33cg-xc48
Record: https://patchnext.com/advisories/cve-2026-40086 (revision 2, source checked 26 Oct 2026, 13:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: rembg 2.0.75. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI rembg: affected < 2.0.75; fixed in 2.0.75

## Suggested inspection (read-only)
- `python -m pip show rembg`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on rembg.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-3wqj-33cg-xc48 (OSV record GHSA-3wqj-33cg-xc48 lists affected ranges: PyPI rembg >=0 <2.0.75 (fixed))
- Verified: https://github.com/advisories/GHSA-3wqj-33cg-xc48 (GitHub-reviewed advisory GHSA-3wqj-33cg-xc48 lists affected ranges: PyPI rembg >=0 <2.0.75)

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