Py BcryptApplication · Python
CVE-2013-1895
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 · uneditedThe py-bcrypt module before 0.3 for Python does not properly handle concurrent memory access, which allows attackers to bypass authentication via multiple authentication requests, which trigger the password hash to be overwritten.
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 · moderate confidencepy-bcrypt module before version 0.3 for Python contains a race condition vulnerability where concurrent authentication requests can cause the password hash stored in memory to be overwritten, allowing attackers to bypass authentication by submitting multiple simultaneous login attempts.
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
Py BcryptApplication
< 0.3
FedoraOperating system
= 17= 18CVSS 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
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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 installed py-bcrypt versionRun 'pip show py-bcrypt' or 'python -c "import bcrypt; print(bcrypt.__version__)"'Affected if Version is present and less than 0.3, or the package cannot be found but bcrypt functionality is in use
-
Identify if authentication code uses concurrent requestsReview application source code for threading, multiprocessing, or async handling around login/authentication functionsAffected if Multiple authentication attempts can be processed simultaneously without mutex locks or rate limiting
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Check for absence of application-level locking in auth flowSearch authentication modules for mutex, lock, or synchronization primitives wrapping password verification callsAffected if No locking mechanism protects the bcrypt password comparison from concurrent access
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Verify operating system if on FedoraRun 'cat /etc/fedora-release' to confirm the Fedora versionAffected if Running Fedora 17 or Fedora 18 with py-bcrypt < 0.3 in use
You are affected if py-bcrypt version is below 0.3 AND your application processes multiple authentication requests concurrently without application-level mutex protection.
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 data0.3
Update py-bcrypt to version 0.3 or later to obtain the corrected concurrent memory handling. As a compensating control, implement application-level rate limiting or mutex locks around authentication logic until the library is upgraded.
Fix this in Py Bcrypt
Scoped from the published advisory
- Consultation4.0 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 $3,392.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-1895 — 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-2013-1895 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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- Version or environment caveats, and links to real fixes
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