SciTokens has an Authorization Bypass via Incorrect Scope Path Prefix Checking

Exploitation

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

CVSS

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

EPSS

• CVE-2026-32716: 0.40% estimated exploitation activity in the next 30 days; percentile 33.86 (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 The Enforcer incorrectly validates scope paths by using a simple prefix match (startswith). This allows a token with access to a specific path (e.g., /john) to also access sibling paths that start with the same prefix (e.g., /johnathan, /johnny), which is an Authorization Bypass. Details File: src/scitokens/scitokens.py Methods: validatescp and validatescope Vulnerable Code Snippets: In validatescp (around line 696): In validatescope (around line 722): If normpath (authorized) is /john and normrequestedpath (requested) is /johnathan, startswith returns True, incorrectly granting access. PoC Impact This bug allows a user to access resources they are not authorized for. For example, if a system uses usernames as top-level directories in a shared storage, a user john might be able to read or write to the directory of user johnathan simply because their names share a prefix.

Published by the source

31 Mar 2026, 22:51 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-w8fp-g9rh-34jh

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-w8fp-g9rh-34jh

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# Patch Next advisory brief: CVE-2026-32716

Advisory: SciTokens has an Authorization Bypass via Incorrect Scope Path Prefix Checking
IDs: CVE-2026-32716, GHSA-w8fp-g9rh-34jh
Record: https://patchnext.com/advisories/cve-2026-32716 (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: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: scitokens 1.9.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI scitokens: affected < 1.9.6; fixed in 1.9.6

## Suggested inspection (read-only)
- `python -m pip show scitokens`: 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 scitokens.
- 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-w8fp-g9rh-34jh (OSV record GHSA-w8fp-g9rh-34jh lists affected ranges: PyPI scitokens >=0 <1.9.6 (fixed))
- Verified: https://github.com/advisories/GHSA-w8fp-g9rh-34jh (GitHub-reviewed advisory GHSA-w8fp-g9rh-34jh lists affected ranges: PyPI scitokens >=0 <1.9.6)

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