Lemur: Sub-CA creation never checks AuthorityPermission on the parent authority

Exploitation

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

CVSS

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

EPSS

• CVE-2026-71317: 0.10% estimated exploitation activity in the next 30 days; percentile 1.07 (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 Repo under test: https://github.com/Netflix/lemur When ADMINONLYAUTHORITYCREATION=False (an explicitly supported and documented configuration), POST /api/1/authorities with type=subca never verifies that the caller holds AuthorityPermission on the supplied parent authority. The parent field is resolved by AssociatedAuthoritySchema via a raw fetchobjects(Authority, data) lookup, then passed straight through service.create → mint → cryptography-issuer.createauthority, which loads options["parent"].authoritycertificate.privatekey and signs a brand-new intermediate CA on the caller's behalf. Any authenticated non-read-only user can therefore mint a sub-CA chained to any internal root whose private key Lemur holds — including roots they hold no role on — attach a role they already belong to, and immediately issue or offline-sign trusted leaf certificates for arbitrary names. Affected route POST /api/1/authorities (with type=subca) Affected code - lemur/authorities/views.py:231 —…

Published by the source

18 Aug 2026, 20:51 UTC

Last modified by the source

18 Aug 2026, 20:51 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-g7p5-89mh-248h

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# Patch Next advisory brief: CVE-2026-71317

Advisory: Lemur: Sub-CA creation never checks `AuthorityPermission` on the parent authority
IDs: CVE-2026-71317, GHSA-g7p5-89mh-248h
Record: https://patchnext.com/advisories/cve-2026-71317 (revision 1, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: lemur 1.9.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI lemur: affected <= 1.9.2; fixed in 1.9.3

## Suggested inspection (read-only)
- `python -m pip show lemur`: 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 lemur.
- 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://github.com/advisories/GHSA-g7p5-89mh-248h (GitHub-reviewed advisory GHSA-g7p5-89mh-248h lists affected ranges: PyPI lemur >=0 <=1.9.2)

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