CVE-2011-2523

CRITICALNVD 9.89.8—Trending — 3 sources updated this weekWeaponized

9.8

vsftpd 2.3.4 downloaded between 20110630 and 20110703 contains a backdoor which opens a shell on port 6200/tcp.

CVSS v3: 9.8
EG Score: 9.8(high)
EPSS: 99.9%
KEV: Not listed

Published

November 27, 2019

Last Modified

November 21, 2024

References (12)

secalert@redhathttp://packetstormsecurity.com/files/162145/vsftpd-2.3.4-Backdoor-Command-Execution.html
secalert@redhathttps://access.redhat.com/security/cve/cve-2011-2523
secalert@redhathttps://packetstormsecurity.com/files/102745/VSFTPD-2.3.4-Backdoor-Command-Execution.html
secalert@redhathttps://security-tracker.debian.org/tracker/CVE-2011-2523
secalert@redhathttps://vigilance.fr/vulnerability/vsftpd-backdoor-in-version-2-3-4-10805
secalert@redhathttps://www.openwall.com/lists/oss-security/2011/07/11/5
af854a3a-2127-422b-91ae-364da2661108http://packetstormsecurity.com/files/162145/vsftpd-2.3.4-Backdoor-Command-Execution.html
af854a3a-2127-422b-91ae-364da2661108https://access.redhat.com/security/cve/cve-2011-2523
af854a3a-2127-422b-91ae-364da2661108https://packetstormsecurity.com/files/102745/VSFTPD-2.3.4-Backdoor-Command-Execution.html
af854a3a-2127-422b-91ae-364da2661108https://security-tracker.debian.org/tracker/CVE-2011-2523
af854a3a-2127-422b-91ae-364da2661108https://vigilance.fr/vulnerability/vsftpd-backdoor-in-version-2-3-4-10805
af854a3a-2127-422b-91ae-364da2661108https://www.openwall.com/lists/oss-security/2011/07/11/5

Weakness Classification(1)

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

CWE-78OS Command Injection

Data Freshness Timeline

(refreshed 6× in last 7d / 6× 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.

2026-05-31 22:28 UTCepss_batch
2026-05-31 22:28 UTCepss_batch
2026-05-27 13:38 UTCepss_batch
2026-05-27 13:38 UTCepss_batch
2026-05-27 11:04 UTCEG score recompute
2026-05-27 11:04 UTCGHSA enrichment

Publicly available exploits

(10 references)

Working exploit code is in the public domain (8 GitHub PoCs) (2 Exploit-DB entries). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

GitHub PoCBolivarJ/CVE-2011-2523
First seen Aug 11, 2025
Python exploit for vsftpd 2.3.4 - Backdoor Command Execution
Open source ↗
GitHub PoCGill-Singh-A/vsFTP-2.3.4-Remote-Root-Shell-Exploit
First seen Aug 3, 2024
A Simple Python Program that uses gets a Remote Root Shell on the Target Device by exploiting a Vulnerability (CVE-2011-2523) present in vsFTP 2.3.4
Open source ↗
GitHub PoC4m3rr0r/CVE-2011-2523-poc
First seen Nov 28, 2023
Python exploit for CVE-2011-2523 (VSFTPD 2.3.4 Backdoor Command Execution)
Open source ↗
GitHub PoCLynk4/CVE-2011-2523
First seen May 9, 2023
Python exploit for vsftpd 2.3.4 - Backdoor Command Execution
Open source ↗
GitHub PoCcowsecurity/CVE-2011-2523
First seen Feb 5, 2023
CVE-2011-2523 exploit
Open source ↗
GitHub PoCMFernstrom/OffensivePascal-CVE-2011-2523
First seen May 27, 2022
FreePascal implementation of the vsFTPD 2.3.4 CVE-2011-2523
Open source ↗
GitHub PoCpadsalatushal/CVE-2011-2523
First seen Nov 7, 2021
Python exploit for vsftpd 2.3.4 - Backdoor Command Execution
Open source ↗
GitHub PoCnobodyatall648/CVE-2011-2523
First seen May 1, 2021
vsftpd 2.3.4 Backdoor Exploit
Open source ↗
Exploit-DBEDB-49757✓ verified
First seen Apr 12, 2021
vsftpd 2.3.4 - Backdoor Command Execution
Open source ↗
Exploit-DBEDB-17491✓ verified
First seen Jul 5, 2011
vsftpd 2.3.4 - Backdoor Command Execution (Metasploit)
Open source ↗

Frequently asked(5)

What is CVE-2011-2523?

CVE-2011-2523 is a critical vulnerability published on November 27, 2019. vsftpd 2.3.4 downloaded between 20110630 and 20110703 contains a backdoor which opens a shell on port 6200/tcp.

When was CVE-2011-2523 disclosed?

CVE-2011-2523 was first published in the National Vulnerability Database on November 27, 2019, 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-2011-2523 actively exploited?

CVE-2011-2523 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2011-2523?

CVE-2011-2523 has a CVSS v3 base score of 9.8 (NVD).

How do I remediate CVE-2011-2523?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2011-2523, 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-2011-2523

📅 Published

🔄 Last Modified

🔗 References (12)

Weakness Classification(1)

Data Freshness Timeline

Publicly available exploits

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2011-2523?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (12)

Frequently asked(5)

Related CVEs(same CWE)