python-tuf: Platform-dependent delegation path matching
- Exploited
- No known exploitation
- Fix
- Fixed in 7.0.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 7.0.0.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 14/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
python-tuf, a Python reference implementation of The Update Framework, has a flaw in how it matches delegation paths on Windows, where the comparison ignores case. An attacker with local access and no login can get a client to accept a target from the wrong delegation when the repository has path delegations that differ only by case and the attacker-controlled role is checked first, which affects Windows clients only.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original 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.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure?/25Unknown. No advisory context yet
- Reach10/20Affects PyPI packages
- Severity4/10CVSS 4.0
- No patch0/5No signal
What would change the score
- Would score about 69 if added to CISA KEV
- Would score about 64 if CISA's SSVC rates exploitation active
- Would score about 36 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 7.0.0.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- theupdateframework python-tuf
fixed in 7.0.0
- tufPyPI
fixed in 7.0.0
Evidence 3
- Advisory
- Repository
- Repository
Corrections
None so far.
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Questions about CVE-2026-123806
Is CVE-2026-123806 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-123806?
python-tuf: before 7.0.0. tuf (PyPI): before 7.0.0.Source: cve.now feed data
How do I fix CVE-2026-123806?
Upgrade to a fixed version: 7.0.0.Source: cve.now feed data