CVE-2026-71303

HIGHPre-NVD 7.77.7—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 81% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
7.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.7Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Lemur manages TLS certificate creation. Prior to 1.9.3, _validate_acme_url enforced ACME_DIRECTORY_HOST_ALLOWLIST when an authority was created, but PUT /api/1/authorities/ passed options to lemur/authorities/service.py without applying the same check. A user holding an authority role could replace the stored acme_url with an internal service or instance-metadata URL such as 169.254.169.254. The next issuance operation loaded that value and passed it to ClientV2.get_directory, causing an outbound request from the Lemur backend. This bypassed the creation-time mitigation for CVE-2026-55166 and could expose internal services or cloud metadata. The fix revalidates acme_url whenever authority options are updated. This issue is fixed in version 1.9.3.

CVSS v3
7.7
EG Score
7.7(medium)
EG Risk
51(Track)
EG Risk 51/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity77% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
19%
KEV
Not listed

Published

August 18, 2026

Last Modified

September 8, 2026

Advisory Details (3)

Auto-updated Aug 18, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
github_release Patch Available

v1.9.3

Patch available: Netflix/lemur v1.9.3

https://github.com/Netflix/lemur/releases/tag/v1.9.3
github_commit Patch Available

commit edca0390f930 (Netflix/lemur)

Patch available: Netflix/lemur v1.9.3 (contains commit edca0390f930)

https://github.com/Netflix/lemur/commit/edca0390f930344d65ff4ca37a669c2320e3dfad
github Patch Available🟡 PoC Available

Incomplete fix for GHSA-v2wp-frmc-5q3v -- ACME authority update endpoint allows non-admin to replace `acme_url` with internal IP, bypassing allowlist · Advisory · Netflix/lemur · GitHub

https://github.com/Netflix/lemur/security/advisories/GHSA-v5rc-cpwc-cfpr

Vendor Advisories for CVE-2026-71303(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
lemur0.11.0 ... 1.9.2 (20 versions)1.9.3—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 47× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-18 23:21 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 01:41 UTCEG score recompute
  4. 2026-09-16 15:58 UTCEG score recompute
  5. 2026-09-16 14:08 UTCEPSS rescore
  6. 2026-09-16 05:15 UTCEPSS rescore
  7. 2026-09-15 06:32 UTCEG score recompute
  8. 2026-09-15 03:12 UTCEPSS rescore
  9. 2026-09-13 20:35 UTCEG score recompute
  10. 2026-09-12 22:55 UTCEG score recompute
  11. 2026-09-12 15:02 UTCEPSS rescore
  12. 2026-09-12 01:15 UTCEG score recompute
  13. 2026-09-11 14:53 UTCEPSS rescore
  14. 2026-09-11 14:25 UTCEG score recompute
  15. 2026-09-10 16:44 UTCEG score recompute
  16. 2026-09-10 09:35 UTCEPSS rescore
  17. 2026-09-09 08:06 UTCEG score recompute
  18. 2026-09-08 22:01 UTCEPSS rescore
  19. 2026-09-07 16:07 UTCEG score recompute
  20. 2026-09-06 14:24 UTCEG score recompute
  21. 2026-09-06 13:48 UTCEPSS rescore
  22. 2026-09-05 16:44 UTCEG score recompute
  23. 2026-09-04 19:00 UTCEG score recompute
  24. 2026-09-04 07:48 UTCEG score recompute
  25. 2026-09-04 05:07 UTCEPSS rescore
Show 29 more
  1. 2026-09-02 21:56 UTCEG score recompute
  2. 2026-09-02 14:12 UTCEPSS rescore
  3. 2026-09-01 20:15 UTCEG score recompute
  4. 2026-09-01 13:54 UTCEPSS rescore
  5. 2026-08-30 23:15 UTCEG score recompute
  6. 2026-08-30 19:17 UTCEPSS rescore
  7. 2026-08-30 01:28 UTCEG score recompute
  8. 2026-08-30 01:22 UTCEPSS rescore
  9. 2026-08-29 03:46 UTCEG score recompute
  10. 2026-08-28 21:42 UTCEPSS rescore
  11. 2026-08-27 21:11 UTCEG score recompute
  12. 2026-08-26 23:32 UTCEG score recompute
  13. 2026-08-26 14:47 UTCEPSS rescore
  14. 2026-08-25 15:03 UTCEG score recompute
  15. 2026-08-25 13:49 UTCEPSS rescore
  16. 2026-08-24 17:23 UTCEG score recompute
  17. 2026-08-23 08:53 UTCEG score recompute
  18. 2026-08-23 00:19 UTCEPSS rescore
  19. 2026-08-22 00:23 UTCEG score recompute
  20. 2026-08-21 23:49 UTCEPSS rescore
  21. 2026-08-21 02:43 UTCEG score recompute
  22. 2026-08-20 22:56 UTCEPSS rescore
  23. 2026-08-19 18:14 UTCEG score recompute
  24. 2026-08-19 17:04 UTCEPSS rescore
  25. 2026-08-19 07:14 UTCEG score recompute
  26. 2026-08-18 20:22 UTCEG score recompute
  27. 2026-08-18 19:53 UTCEG score recompute
  28. 2026-08-18 19:19 UTCEG score recompute
  29. 2026-08-18 19:18 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-71303?
CVE-2026-71303 is a high vulnerability published on August 18, 2026. Lemur manages TLS certificate creation. Prior to 1.9.3, validateacmeurl enforced ACMEDIRECTORYHOSTALLOWLIST when an authority was created, but PUT /api/1/authorities/ passed options to lemur/authorities/service.py without applying the same check. A user holding an authority role could replace the…
When was CVE-2026-71303 disclosed?
CVE-2026-71303 was first published in the National Vulnerability Database on August 18, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-71303 actively exploited?
CVE-2026-71303 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 80.8% of all scored CVEs.
What is the CVSS score of CVE-2026-71303?
CVE-2026-71303 has a CVSS v3 base score of 7.7 (NVD).
How do I remediate CVE-2026-71303?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-71303, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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