Lemur: Missing authorization check on POST /certificates/ /export for plugins with requires_key = False

Exploitation

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

CVSS

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

EPSS

• CVE-2026-71322: 0.23% estimated exploitation activity in the next 30 days; percentile 14.33 (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 CertificateExport handler in lemur/certificates/views.py nests its entire ownership / CertificatePermission check inside an if plugin.requireskey: branch. When the selected export plugin advertises requireskey = False, the authorization check is skipped entirely and any authenticated user can invoke plugin.export(cert.body, cert.chain, cert.privatekey, options) against a certificate they do not own. The handler additionally writes a "keyview" audit-log event for every call, regardless of whether the plugin actually accessed the private key, polluting the audit trail with false positives. Root Cause lemur/certificates/views.py:1573: The authorization gate is structurally inside the if plugin.requireskey: block. With requireskey = False, control falls straight through to plugin.export(...) with no ownership check. The cert.privatekey is passed to the plugin regardless of the flag — the flag only describes what the plugin advertises it needs, not what it actually receives.…

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-4h97-p9wq-chqj

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-71322

Advisory: Lemur: Missing authorization check on POST /certificates/ /export for plugins with requires_key = False
IDs: CVE-2026-71322, GHSA-4h97-p9wq-chqj
Record: https://patchnext.com/advisories/cve-2026-71322 (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 4.3)
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 < 1.9.3; 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-4h97-p9wq-chqj (GitHub-reviewed advisory GHSA-4h97-p9wq-chqj lists affected ranges: PyPI lemur >=0 <1.9.3)

Commands are suggestions: review each one before running it.