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Vulnerabilities

Vulnerability · CVE-2026-123806

tuf has platform-dependent delegation path matching

Published May 28, 2026 · catalog updated Nov 9, 2026 · Red Hat Red Hat Enterprise Linux

Last checked Nov 11, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-123806. EPSS is 0.13%. Act only if a listed version of Red Hat Red Hat Enterprise Linux is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium4.0
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.13%
Remediation
Advisory link
Affected products
PyPI tuf

uses to decide whether a given target path is authorized by a delegation's glob pattern. Python's calls on both arguments before matching. On POSIX hosts is the identity function; on Windows hosts resolves to , whose lowercases its input and replaces with . As a result, python-tuf's delegation *path pattern* matching is case-sensitive on Linux/macOS but case-INSENSITIVE on Windows. This makes the authorization decision for a target dependent on the host operating system of the client running the updater. The result on Windows is a TUF specification violation in the python-tuf implementation. ## Vulnerable code (HEAD ): source (Python 3.12, unchanged in current mainline): ## Fix Replace with , which is explicitly documented as "not applying case normalization", so it behaves identically across platforms. ## Attack 1. A TUF repository with two path-based delegations whose patterns differ only in case — for example, and . 2. The "attacker" delegation is listed BEFORE the "legit" delegation in the delegation order. 3. The client searches for : on Windows, it will find the "attacker" provided target "Foo/something". ## Exploitability caveats * The attack needs a repository configuration with case-colliding delegation path patterns. The attacker must control one of the delegated roles. * Delegation ordering matters: the attacker-controlled role must be visited BEFORE the legit role in the pre-order walk. * The client must run on Windows. No effect on Linux/macOS. ## Credit Reporter: Koda Reef @kodareef5 Advisory edits: Jussi Kukkonen @jku

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • PyPI tuf0 → 7.0.0

How to fix CVE-2026-123806

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-123806. EPSS is 0.13%. Act only if a listed version of Red Hat Red Hat Enterprise Linux is installed.

Which versions are affected?

Compare what you have installed with 0 → 7.0.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-178. EPSS 0.13%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. May 28, 2026 · PyPA Advisory Database

    Detected

    uses to decide whether a given target path is authorized by a delegation's glob pattern. Python's calls on both arguments before matching. On POSIX hosts is the identity function; on Windows hosts resolves to , whose lowercases its input and replaces with . As a result, python-tuf's delegation *path pattern* matching is case-sensitive on Linux/macOS but case-INSENSITIVE on Windows. This makes the

  2. Nov 9, 2026 · PyPA Advisory Database

    Fix available

    tuf fixed in 7.0.0

  3. Nov 9, 2026 · PyPA Advisory Database

    Fix available

    tuf fixed in 7.0.0

  4. Nov 9, 2026 · PyPA Advisory Database

    Updated

    uses to decide whether a given target path is authorized by a delegation's glob pattern. Python's calls on both arguments before matching. On POSIX hosts is the identity function; on Windows hosts resolves to , whose lowercases its input and replaces with . As a result, python-tuf's delegation *path pattern* matching is case-sensitive on Linux/macOS but case-INSENSITIVE on Windows. This makes the

Sources

References

Freshness

Last verified in this catalog Nov 10, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • Red Hat Security DataNov 11, 2026
  • FIRST EPSSNov 10, 2026
  • CVE.orgNov 10, 2026
  • PyPA Advisory DatabaseNov 10, 2026