# CVE-2026-123806: python-tuf: Platform-dependent delegation path matching


- **Severity:** Medium 4.0 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 9 Nov 2026
- **Updated:** 9 Nov 2026
- **Also known as:** GHSA-qp9x-wp8f-qgjj, MINI-2mqm-q893-2pgh, MINI-4jcc-f3mx-66p2, MINI-v7f4-x42m-v3qc, UBUNTU-CVE-2026-123806

## What is CVE-2026-123806?

CVE-2026-123806 is a medium-severity vulnerability in theupdateframework python-tuf, published on 9 Nov 2026. 

### Official description

python-tuf is a Python reference implementation of The Update Framework (TUF). Prior to 7.0.0, DelegatedRole._is_target_in_pathpattern in tuf/api/_payload.py uses fnmatch.fnmatch, which applies os.path.normcase before matching and makes delegation path authorization case-insensitive on Windows. When a TUF repository has path-based delegations that differ only by case and an attacker-controlled role is visited before the legitimate role, ngclient can accept an attacker-provided target from the wrong delegation for a requested path. Linux and macOS clients are not affected because their path normalization does not change case. This issue is fixed in 7.0.0.

Weakness: CWE-178 (Improper Handling of Case Sensitivity)

## Which versions are affected by CVE-2026-123806?

1 open source package ship an affected version, including tuf.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `tuf` | PyPI | All versions | 7.0.0 |

## How do I fix CVE-2026-123806?

Upgrade tuf to 7.0.0 or later.

## Is CVE-2026-123806 being exploited?

There is no known exploitation of CVE-2026-123806 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123806 and fix it if it is affected.

What it is: CVE-2026-123806 is a medium-severity vulnerability in theupdateframework python-tuf, published on 9 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-123806 in the wild and no public exploit code.

Affected packages and fixed versions:
- tuf (PyPI): affected all versions; fixed in 7.0.0

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-2026-123806/ (Markdown: https://insights.sbomify.com/CVE-2026-123806/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123806
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123806
- OSV: https://osv.dev/vulnerability/CVE-2026-123806

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123806/
Summaries are generated and may contain mistakes; the official description above is the record.