CVE-2018-20225
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 · uneditedAn issue was discovered in pip (all versions) because it installs the version with the highest version number, even if the user had intended to obtain a private package from a private index. This only affects use of the --extra-index-url option, and exploitation requires that the package does not already exist in the public index (and thus the attacker can put the package there with an arbitrary version number). NOTE: it has been reported that this is intended functionality and the user is responsible for using --extra-index-url securely
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 confidenceWhen pip installs packages using --extra-index-url for private indexes, it still queries the public PyPI and will install the package with the highest version number, even if that version is from the public index. An attacker can register a package with a high version number on PyPI that matches a private package name, causing pip to install the attacker's malicious package instead of the intended private package.
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 dataall 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
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/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 pip configuration files for extra index URLInspect pip.conf (global or per-user), pip.ini, or pyproject.toml for the presence of --extra-index-url or extra-index-url settingAffected if --extra-index-url is configured and points to a private package index while public PyPI remains accessible
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Check environment variable for extra index URLExamine the PIP_EXTRA_INDEX_URL environment variable in your system environmentAffected if PIP_EXTRA_INDEX_URL is set and public PyPI is not disabled
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Check if hash verification mode is enabledLook for --require-hashes flag in pip install commands, CI/CD pipelines, or configuration filesAffected if Hash verification is NOT enabled (pip is vulnerable if --require-hashes is absent)
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Identify private package names that might conflict with PyPIReview packages installed from private indexes and check if any share names with packages on public PyPIAffected if Private packages have names that exist on public PyPI and are installed via --extra-index-url without hash verification
You are affected if pip uses --extra-index-url to a private index while public PyPI remains accessible and hash verification (--require-hashes) is not enabled.
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 dataUse --index-url instead of --extra-index-url to prevent pip from consulting public PyPI for private packages, or implement package hash verification using --require-hashes mode to ensure package integrity.
- Consultation2.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-20225 — 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-2018-20225 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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