CVSS 3.1
4.0 mediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NCVE-2026-123806 python-tuf: Platform-dependent delegation path matching
Medium (4.0) in theupdateframework python-tuf. EPSS 0.1% estimated probability of exploitation activity in the next 30 days. Fixed in tuf 7.0.0.
On this page
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.
Severity
- EPSS
- 0.1% estimated probability of exploitation activity in the next 30 days; 3rd percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: no · Technical impact: partial, assessed 2026-11-13. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-178 Improper Handling of Case Sensitivity
- Published
- Modified
- Assigned by
- GitHub_M (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
Ask an AI about this CVE
Show the prompt
Explain CVE-2026-123806 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-123806?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-123806?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-123806 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Badge for a README or a site
An image that stays current: it is drawn from the data each time it is fetched (a host that proxies images, as GitHub does, may show its copy for a while). Markdown:
[](https://cve.bz/cve/CVE-2026-123806)
HTML:
<a href="https://cve.bz/cve/CVE-2026-123806"><img src="https://cve.bz/cve/badge/CVE-2026-123806.svg" alt="CVE-2026-123806"></a>
Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| theupdateframework python-tuf | < 7.0.0 |
Fix and patched versions
tuf(PyPI): fixed in 7.0.0
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-qp9x-wp8f-qgjj | PyPI | tuf | <7.0.0 | 7.0.0 |
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Ubuntu | 26.04:LTS, 26.10 | python-tuf | no fix listed | UBUNTU-CVE-2026-123806 |
From the distributions' data via OSV.dev: Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Ubuntu.