CVE-2020-35729

CRITICALNVD 9.89.8—Weaponized

9.8

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(high)
EPSS: 99.6%
KEV: Not listed

Published

December 27, 2020

Last Modified

November 21, 2024

References (10)

cve@mitrehttp://packetstormsecurity.com/files/160798/Klog-Server-2.4.1-Command-Injection.html
cve@mitrehttp://packetstormsecurity.com/files/161123/Klog-Server-2.4.1-Command-Injection.html
cve@mitrehttp://packetstormsecurity.com/files/161410/Klog-Server-2.4.1-Command-Injection.html
cve@mitrehttps://github.com/mustgundogdu/Research/blob/main/KLOG_SERVER/Exploit_Code
cve@mitrehttps://github.com/mustgundogdu/Research/blob/main/KLOG_SERVER/README.md
af854a3a-2127-422b-91ae-364da2661108http://packetstormsecurity.com/files/160798/Klog-Server-2.4.1-Command-Injection.html
af854a3a-2127-422b-91ae-364da2661108http://packetstormsecurity.com/files/161123/Klog-Server-2.4.1-Command-Injection.html
af854a3a-2127-422b-91ae-364da2661108http://packetstormsecurity.com/files/161410/Klog-Server-2.4.1-Command-Injection.html
af854a3a-2127-422b-91ae-364da2661108https://github.com/mustgundogdu/Research/blob/main/KLOG_SERVER/Exploit_Code
af854a3a-2127-422b-91ae-364da2661108https://github.com/mustgundogdu/Research/blob/main/KLOG_SERVER/README.md

Weakness Classification(1)

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

CWE-78OS Command Injection

Data Freshness Timeline

(refreshed 7× in last 7d / 15× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-05 06:08 UTCepss_batch
2026-06-05 06:08 UTCepss_batch
2026-06-04 13:10 UTCepss_batch
2026-06-04 13:10 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-26 22:58 UTCEG score recompute
2026-05-26 22:58 UTCGHSA enrichment
2026-05-26 13:42 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

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 ↗

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 99.6% 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.

Dependency Blast Radius

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CVE-2020-35729

📅 Published

🔄 Last Modified

🔗 References (10)

Weakness Classification(1)

Data Freshness Timeline

Publicly available exploits

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2020-35729?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (10)

Frequently asked(5)

Related CVEs(same CWE)