CVE-2020-35391

CRITICALNVD 9.69.6—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.6 under NVD CVSS v3. EPSS exploit probability: 35.0%, top 2% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Elevated
9.6
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 35%CVSS: 9.6Exploit: NoneExposed: 0

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

Tenda N300 F3 12.01.01.48 devices allow remote attackers to obtain sensitive information (possibly including an http_passwd line) via a direct request for cgi-bin/DownloadCfg/RouterCfm.cfg, a related issue to CVE-2017-14942. NOTE: the vulnerability report may suggest that either a ? character must be placed after the RouterCfm.cfg filename, or that the HTTP request headers must be unusual, but it is not known why these are relevant to the device's HTTP response behavior.

CVSS v3
9.6
EG Score
9.6(medium)
EG Risk
64(Track*)
EG Risk 64/100SSVC: 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
Severity96% × 45%
Exploitation40% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
98.3%
KEV
Not listed

Published

January 1, 2021

Last Modified

November 21, 2024

References (4)

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 32× 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. 2026-07-23 01:53 UTCEG score recompute
  2. 2026-07-22 22:39 UTCEG score recompute▲ 3.10
  3. 2026-07-22 14:05 UTCEPSS rescore
  4. 2026-07-21 15:22 UTCEPSS rescore
  5. 2026-07-21 15:22 UTCEPSS rescore
  6. 2026-07-20 17:04 UTCEPSS rescore
  7. 2026-07-20 17:04 UTCEPSS rescore
  8. 2026-07-19 14:28 UTCEPSS rescore
  9. 2026-07-19 14:28 UTCEPSS rescore
  10. 2026-07-16 16:59 UTCEPSS rescore
  11. 2026-07-15 16:55 UTCEPSS rescore
  12. 2026-07-15 16:55 UTCEPSS rescore
  13. 2026-07-15 01:57 UTCEPSS rescore
  14. 2026-07-13 06:10 UTCEPSS rescore
  15. 2026-07-13 06:10 UTCEPSS rescore
  16. 2026-07-12 05:44 UTCEPSS rescore
  17. 2026-07-11 08:25 UTCEPSS rescore
  18. 2026-07-11 08:25 UTCEPSS rescore
  19. 2026-07-09 19:07 UTCEPSS rescore
  20. 2026-07-08 15:12 UTCEPSS rescore
  21. 2026-07-06 02:21 UTCEPSS rescore
  22. 2026-07-06 02:21 UTCEPSS rescore
  23. 2026-06-29 14:04 UTCEPSS rescore
  24. 2026-06-28 04:54 UTCEPSS rescore
  25. 2026-06-28 04:54 UTCEPSS rescore
Show 37 more
  1. 2026-06-27 03:06 UTCEPSS rescore
  2. 2026-06-27 03:06 UTCEPSS rescore
  3. 2026-06-25 13:48 UTCEPSS rescore
  4. 2026-06-24 14:03 UTCEPSS rescore
  5. 2026-06-24 14:03 UTCEPSS rescore
  6. 2026-06-23 21:31 UTCEPSS rescore
  7. 2026-06-23 21:31 UTCEPSS rescore
  8. 2026-06-21 01:57 UTCEPSS rescore
  9. 2026-06-18 17:50 UTCEPSS rescore
  10. 2026-06-18 17:50 UTCEPSS rescore
  11. 2026-06-17 17:50 UTCEPSS rescore
  12. 2026-06-16 17:50 UTCEPSS rescore
  13. 2026-06-15 17:46 UTCEPSS rescore
  14. 2026-06-12 23:10 UTCEPSS rescore
  15. 2026-06-11 13:58 UTCEPSS rescore
  16. 2026-06-10 22:16 UTCEPSS rescore
  17. 2026-06-10 13:20 UTCEPSS rescore
  18. 2026-06-06 13:46 UTCEPSS rescore
  19. 2026-06-06 13:45 UTCEPSS rescore
  20. 2026-06-05 22:45 UTCEPSS rescore
  21. 2026-06-05 22:45 UTCEPSS rescore
  22. 2026-06-05 06:08 UTCEPSS rescore
  23. 2026-06-05 06:08 UTCEPSS rescore
  24. 2026-06-04 13:10 UTCEPSS rescore
  25. 2026-06-04 13:10 UTCEPSS rescore
  26. 2026-06-02 20:11 UTCEPSS rescore
  27. 2026-06-02 20:11 UTCEPSS rescore
  28. 2026-05-31 22:29 UTCEPSS rescore
  29. 2026-05-31 22:29 UTCEPSS rescore
  30. 2026-05-31 00:15 UTCEPSS rescore
  31. 2026-05-31 00:15 UTCEPSS rescore
  32. 2026-05-28 13:43 UTCEPSS rescore
  33. 2026-05-28 13:43 UTCEPSS rescore
  34. 2026-05-26 22:41 UTCEG score recompute
  35. 2026-05-26 22:41 UTCGHSA enrichment
  36. 2026-05-26 07:17 UTCEPSS rescore
  37. 2026-05-26 07:17 UTCEPSS rescore

Publicly available exploits

(4 references)

Working exploit code is in the public domain (3 GitHub PoCs) (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoC4d000/Tenda-F3-V4
    First seen Mar 2, 2025

    Python script to exploit CVE-2020-35391 on Tenda F3 V3/V4 routers, enabling unauthorized download of configuration, flash, and syslog files.

    Open source ↗
  • Exploit-DBEDB-51317
    First seen Apr 7, 2023

    Tenda N300 F3 12.01.01.48 - Malformed HTTP Request Header Processing

    Open source ↗
  • GitHub PoCH454NSec/CVE-2020-35391
    First seen Mar 9, 2023

    Tenda f3 Malformed HTTP Request Header Processing Vulnerability.

    Open source ↗
  • GitHub PoCdumitory-dev/CVE-2020-35391-POC
    First seen Feb 5, 2023

    Tenda N300 Authentication Bypass via Malformed HTTP Request Header

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2020-35391?
CVE-2020-35391 is a critical vulnerability published on January 1, 2021. Tenda N300 F3 12.01.01.48 devices allow remote attackers to obtain sensitive information (possibly including an http_passwd line) via a direct request for cgi-bin/DownloadCfg/RouterCfm.cfg, a related issue to CVE-2017-14942. NOTE: the vulnerability report may suggest that either a ? character must…
When was CVE-2020-35391 disclosed?
CVE-2020-35391 was first published in the National Vulnerability Database on January 1, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-35391 actively exploited?
CVE-2020-35391 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 98.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2020-35391?
CVE-2020-35391 has a CVSS v3 base score of 9.6 (NVD).
How do I remediate CVE-2020-35391?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-35391, 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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