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CVE-2026-70667

CVE-2026-70667 · Lemur: SSRF protection in certificate revocation checking bypassable via HTTP redirects and DNS rebinding (incomplete fix for CVE-2026-55162)

This page contains facts from public vulnerability sources. Check the original advisory before updating.

Lemur manages TLS certificate creation. Prior to 1.9.3, _validate_revocation_url in lemur/certificates/verify.py checked the original CRL or OCSP URL but the later request could reach a different destination. The CRL requests.get call followed HTTP redirects without validating each Location target, so a public attacker-controlled URL could redirect to loopback, RFC1918, link-local, or instance-metadata addresses. Validation and connection also performed separate DNS resolutions, creating a time-of-check time-of-use window for DNS rebinding on both CRL and OCSP paths. An operator uploading a certificate through POST /api/1/certificates/upload could therefore induce blind internal requests despite the earlier mitigation. The fix disables redirects and pins validated addresses while preserving the correct Host value. This issue is fixed in version 1.9.3.

CVSS 6.3 · Medium · EPSS 0.2% · Fix available

Published
Updated

Stack: python

Affected products and versions

  • lemur

    Versions
    • < 1.9.3: Affected

    No fix published

  • lemur PyPI

    Versions
    • 0.11.0
    • 0.2.1
    • 0.8.0
    • 0.8.1
    • 0.9.0
    • 1.0.0
    • 1.1.0
    • 1.2.0
    • 1.3.1
    • 1.3.2
    • 1.4.0
    • 1.5.0
    • 1.6.0
    • 1.7.0
    • 1.8.0
    • 1.8.1
    • 1.8.2
    • 1.9.0
    • 1.9.1
    • 1.9.2
    Affected ranges
    • ECOSYSTEM: < 1.9.3

    Update to 1.9.3

Original sources

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