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🐍 PyPI
Not in CISA KEV
HIGH severity

CVE-2010-3494 — pyftpdlib

HIGH

CVE-2010-3494 is a high-severity (CVSS 7.5) CWE-362 vulnerability in pyftpdlib. A fix is available for pyftpdlib — see the affected versions and patch details below.

Concurrent Execution using Shared Resource with Improper Synchronization in pyftpdlib

Also known asGHSA-hw4g-fhcp-x5mqPYSEC-2010-11
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
2.3%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs83th percentile — riskier than 83% of all scored CVEsHighest risk
0.00%0.95%1.91%2.86%0.4%2.3%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🐍pyftpdlib

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Race condition in the FTPHandler class in ftpserver.py in pyftpdlib before 0.5.2 allows remote attackers to cause a denial of service (daemon outage) by establishing and then immediately closing a TCP connection, leading to the accept function having an unexpected value of None for the address, or an ECONNABORTED, EAGAIN, or EWOULDBLOCK error, a related issue to CVE-2010-3492.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIpyftpdliball versions0.5.2pip install --upgrade 'pyftpdlib==0.5.2'

Affected Products

1 product · 7 configurations
Application
pyftpdlibg.rodola
≤ 0.5.1
6 versions
0.10.1.10.2.00.3.00.4.00.5.0

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pyftpdlib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update pyftpdlib to 0.5.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2010-3494 is resolved across your whole dependency graph.

  3. Workarounds

    Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

Race condition in the FTPHandler class in ftpserver.py in pyftpdlib before 0.5.2 allows remote attackers to cause a denial of service (daemon outage) by establishing and then immediately closing a TCP connection, leading to the accept function having an unexpected value of None for the address, or an ECONNABORTED, EAGAIN, or EWOULDBLOCK error, a related issue to CVE-2010-3492.
O3 Security · Impact-Aware SCA

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CVE-2010-3494: pyftpdlib DoS — Fixed in 0.5.2