CVE-2020-35729

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 88.0%, top 0% 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, nvd
Weaponized
9.8
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 88%
CISA-KEV: Not listedEPSS: 88%CVSS: 9.8Exploit: NoneExposed: 0

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

KLog Server 2.4.1 allows OS command injection via shell metacharacters in the actions/authenticate.php user parameter.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
84(Track*)
EG Risk 84/100SSVC: 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
Severity98% × 45%
Exploitation88% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
99.8%
KEV
Not listed

Published

December 27, 2020

Last Modified

November 21, 2024

Advisory Details (5)

Auto-updated Jun 19, 2026
No patch confirmed yet.
generic

Research/KLOG_SERVER/README.md at main · mustgundogdu/Research · GitHub

https://github.com/mustgundogdu/Research/blob/main/KLOG_SERVER/README.md
generic

Research/KLOG_SERVER/Exploit_Code at main · mustgundogdu/Research · GitHub

https://github.com/mustgundogdu/Research/blob/main/KLOG_SERVER/Exploit_Code
generic

Temporarily Offline

http://packetstormsecurity.com/files/161410/Klog-Server-2.4.1-Command-Injection.html
generic

Temporarily Offline

http://packetstormsecurity.com/files/161123/Klog-Server-2.4.1-Command-Injection.html
generic

Temporarily Offline

http://packetstormsecurity.com/files/160798/Klog-Server-2.4.1-Command-Injection.html

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 11× 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. 2026-07-22 14:05 UTCEPSS rescore
  4. 2026-07-21 15:22 UTCEPSS rescore
  5. 2026-07-21 15:22 UTCEPSS rescore
  6. 2026-07-16 16:59 UTCEPSS rescore
  7. 2026-07-13 22:27 UTCEPSS rescore
  8. 2026-07-13 22:27 UTCEPSS rescore
  9. 2026-06-30 23:20 UTCEPSS rescore
  10. 2026-06-30 23:20 UTCEPSS rescore
  11. 2026-06-25 13:48 UTCEPSS rescore
  12. 2026-06-23 21:31 UTCEPSS rescore
  13. 2026-06-23 21:31 UTCEPSS rescore
  14. 2026-06-17 17:50 UTCEPSS rescore
  15. 2026-06-15 17:46 UTCEPSS rescore
  16. 2026-06-14 23:15 UTCEPSS rescore
  17. 2026-06-13 22:58 UTCEPSS rescore
  18. 2026-06-12 23:10 UTCEPSS rescore
  19. 2026-06-10 22:16 UTCEPSS rescore
  20. 2026-06-10 13:20 UTCEPSS rescore
  21. 2026-06-07 15:23 UTCEPSS rescore
  22. 2026-06-07 15:23 UTCEPSS rescore
  23. 2026-06-07 15:23 UTCEPSS rescore
  24. 2026-06-06 13:46 UTCEPSS rescore
  25. 2026-06-06 13:45 UTCEPSS rescore
Show 17 more
  1. 2026-06-05 22:45 UTCEPSS rescore
  2. 2026-06-05 22:45 UTCEPSS rescore
  3. 2026-06-05 06:08 UTCEPSS rescore
  4. 2026-06-05 06:08 UTCEPSS rescore
  5. 2026-06-04 13:10 UTCEPSS rescore
  6. 2026-06-04 13:10 UTCEPSS rescore
  7. 2026-06-02 20:11 UTCEPSS rescore
  8. 2026-06-02 20:11 UTCEPSS rescore
  9. 2026-06-01 13:50 UTCEPSS rescore
  10. 2026-05-28 13:43 UTCEPSS rescore
  11. 2026-05-28 13:43 UTCEPSS rescore
  12. 2026-05-26 22:58 UTCEG score recompute
  13. 2026-05-26 22:58 UTCGHSA enrichment
  14. 2026-05-26 13:42 UTCEPSS rescore
  15. 2026-05-26 13:42 UTCEPSS rescore
  16. 2026-05-26 07:17 UTCEPSS rescore
  17. 2026-05-26 07:17 UTCEPSS rescore

Publicly available exploits

(5 references)

Working exploit code is in the public domain (1 Metasploit module) (1 GitHub PoC) (2 Exploit-DB entries). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCAl1ex/CVE-2020-35729
    First seen Apr 9, 2021

    CVE-2020-35729

    Open source ↗
  • Exploit-DBEDB-49474✓ verified
    First seen Jan 25, 2021

    Klog Server 2.4.1 - Unauthenticated Command Injection (Metasploit)

    Open source ↗
  • Exploit-DBEDB-49366✓ verified
    First seen Jan 5, 2021

    Klog Server 2.4.1 - Command Injection (Unauthenticated)

    Open source ↗
  • Metasploitexploit/linux/http/klog_server_authenticate_user_unauth_command_injection✓ verified
    First seen Dec 27, 2020

    Klog Server authenticate.php user Unauthenticated Command Injection

    Open source ↗
  • Nucleihttp/cves/2020/CVE-2020-35729.yaml
    First seen Jan 1, 2020

    Klog Server <=2.41 - Unauthenticated Command Injection

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2020-35729?
CVE-2020-35729 is a critical vulnerability published on December 27, 2020. KLog Server 2.4.1 allows OS command injection via shell metacharacters in the actions/authenticate.php user parameter.
When was CVE-2020-35729 disclosed?
CVE-2020-35729 was first published in the National Vulnerability Database on December 27, 2020, 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-2020-35729 actively exploited?
CVE-2020-35729 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2020-35729?
CVE-2020-35729 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2020-35729?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-35729, 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.

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