PythonApplication
CVE-2019-9674
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedLib/zipfile.py in Python through 3.7.2 allows remote attackers to cause a denial of service (resource consumption) via a ZIP bomb.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidencePython's zipfile.py library through version 3.7.2 does not properly validate or limit the expansion ratio of compressed files, allowing a specially crafted ZIP bomb (highly compressed archive) to cause excessive resource consumption during decompression, resulting in denial of service.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
PythonApplication
>= 3.2, <= 3.8
Ubuntu LinuxOperating system
= 12.04= 14.04= 16.04= 18.04= 20.04all versionsCVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check the Python interpreter versionRun 'python3 --version' or 'python --version' to determine the installed Python versionAffected if The version is 3.2 through 3.8 inclusive (versions prior to 3.7.3 are vulnerable)
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Identify if the application uses the zipfile moduleSearch the application codebase for 'import zipfile' statements or usage of ZipFile classAffected if The application imports or uses Python's zipfile module to process archives
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Determine if the application processes untrusted ZIP archivesReview code that handles ZIP file extraction - look for calls to extract(), extractall(), or read() methods on ZipFile objects, especially with user-supplied archivesAffected if The application extracts or reads ZIP files from untrusted or external sources without ratio validation
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Check for application-level decompression ratio limitsSearch the codebase for any manual validation of uncompressed versus compressed size ratios (commonly check for ratios exceeding a threshold before extraction)Affected if No application-level ratio limits are implemented and the Python version falls within the affected range
You are affected if your Python version is between 3.2 and 3.8 and your application uses the zipfile module to process untrusted or external ZIP archives without implementing custom ratio validation.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpdate Python to version 3.7.3 or later where the vulnerability is patched, or implement application-level validation to limit decompression ratios before processing ZIP files.
Fix this in Python
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-9674 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2019-9674 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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