PythonApplication
CVE-2017-17522
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/webbrowser.py in Python through 3.6.3 does not validate strings before launching the program specified by the BROWSER environment variable, which might allow remote attackers to conduct argument-injection attacks via a crafted URL. NOTE: a software maintainer indicates that exploitation is impossible because the code relies on subprocess.Popen and the default shell=False setting
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 webbrowser.py module does not validate URLs before passing them to the browser specified in the BROWSER environment variable, potentially allowing argument injection via crafted URLs. However, the maintainer notes that actual exploitation is prevented because the code uses subprocess.Popen with the default shell=False setting, which passes arguments as a list rather than through shell interpretation.
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
<= 3.6.3CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/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 Python versionRun 'python --version' or 'python3 --version' in your environmentAffected if The version displayed is 3.6.3 or earlier (e.g., 3.6.0, 3.6.1, 3.6.2, 3.6.3)
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Identify webbrowser usageSearch your codebase for imports and calls to the webbrowser module, specifically webbrowser.open() or webbrowser.open_new()Affected if Your code uses webbrowser.open() or related functions with URLs from untrusted sources
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Check BROWSER environment variableRun 'echo $BROWSER' on Linux/macOS or 'echo %BROWSER%' on WindowsAffected if The BROWSER environment variable is set to a value that could be influenced by untrusted input
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Verify subprocess configuration in webbrowserInspect the webbrowser.py module in your Python installation (typically in lib/python3.6/webbrowser.py) and confirm Popen uses shell=FalseAffected if The code uses shell=True (your Python version may have been patched differently than standard releases)
You are affected if you run Python 3.6.3 or earlier and your application passes URLs from untrusted sources to webbrowser.open() while the BROWSER environment variable is set to user-controlled values.
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 dataValidate and sanitize all URLs before passing them to webbrowser.open(), and avoid setting the BROWSER environment variable to untrusted or user-controlled values. Consider upgrading to Python 3.6.4+ if available.
Fix this in Python
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,744.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-17522 — 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-2017-17522 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
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