How severe is CVE-2011-2523?

CVE-2011-2523 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2011-2523 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 96% (100th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-2523?

CVE-2011-2523 primarily affects Vsftpd Project Vsftpd. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-2523?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2011-2523 published?

CVE-2011-2523 was published on 2019-11-27 and last updated on 2026-06-16.

CVE-2011-2523

CVE-2011-2523 is a critical-severity vulnerability in Vsftpd Project Vsftpd with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 96% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-78.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 10.0
EPSS exploit prediction: 96% (100th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Vsftpd Project Vsftpd
Published: 2019-11-27
Last modified: 2026-06-16

Description

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

Frequently asked questions

What is CVE-2011-2523?: vsftpd 2.3.4 downloaded between 20110630 and 20110703 contains a backdoor which opens a shell on port 6200/tcp.
How severe is CVE-2011-2523?: CVE-2011-2523 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2011-2523 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 96% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-2523?: CVE-2011-2523 primarily affects Vsftpd Project Vsftpd. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-2523?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2011-2523 published?: CVE-2011-2523 was published on 2019-11-27 and last updated on 2026-06-16.

References

Affected products (4)

cpe:2.3:a:vsftpd_project:vsftpd:2.3.4:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

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