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PolarsslApplication

CVE-2011-4574

CRITICAL · 9.8 CVSS v3.1 Published 2021-10-27
Fix available
A fix is available. Upgrade to 1.1.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
PolarSSL versions prior to v1.1 use the HAVEGE random number generation algorithm. At its heart, this uses timing information based on the processor's high resolution timer (the RDTSC instruction). This instruction can be virtualized, and some virtual machine hosts have chosen to disable this instruction, returning 0s or predictable results.

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 confidence

PolarSSL versions prior to v1.1 use the HAVEGE random number generator which depends on the RDTSC instruction (processor high-resolution timer) for timing-based entropy. In virtualized environments where hypervisors disable or virtualize RDTSC to return predictable values (often 0s), the random number generation becomes severely weakened, compromising all cryptographic operations relying on these random values.

MitigationUpgrade to PolarSSL v1.1 or later which uses a cryptographically secure random number generator not dependent on RDTSC timing. For systems that cannot upgrade, ensure cryptographic operations are not performed in environments where RDTSC is disabled or returns predictable values.

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
PolarsslApplication
Affected:< 1.1.0

CVSS 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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed PolarSSL version
    Run 'polarssl_version' command if available, or check library binary metadata, or look for version defines in header files (often in include/polarssl/version.h)
    Affected if The version is prior to 1.1.0 (e.g., 1.0.x, 0.x.x series)
  2. Verify if HAVEGE is compiled into the library
    Check the PolarSSL configuration file (config.h) for '#define POLARSSL_HAVEGE_C' or inspect the compiled library symbols for havege functions
    Affected if HAVEGE is enabled in the build configuration
  3. Confirm the application uses PolarSSL for cryptographic operations
    Review application code or linked libraries to verify it links against the affected PolarSSL version and calls cryptographic functions (key generation, encryption, etc.)
    Affected if The application uses the vulnerable PolarSSL library for RNG-dependent operations
  4. Check the runtime environment for RDTSC behavior
    Execute a simple test program that calls RDTSC (e.g., inline assembly 'rdtsc' on x86) multiple times to observe if values change predictably or return zeros
    Affected if RDTSC returns predictable/zero values indicating virtualization with timing disabled

You are affected if you are running PolarSSL version prior to 1.1.0 with HAVEGE enabled in a virtualized environment where RDTSC returns predictable values.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Upgrade available Upgrade to 1.1.0 or later
Fixed in 1.1.0
Interim mitigation

Upgrade to PolarSSL v1.1 or later which uses a cryptographically secure random number generator not dependent on RDTSC timing. For systems that cannot upgrade, ensure cryptographic operations are not performed in environments where RDTSC is disabled or returns predictable values.

Recommended fix High confidence

PolarSSL 1.1.0 or later (note: PolarSSL was rebranded to mbed TLS)

  1. Identify the current PolarSSL version in use by checking library files or dependencies
  2. Download PolarSSL version 1.1.0 or later from the official repository (tls.mbed.org or GitHub)
  3. Replace the existing PolarSSL library files with the new version
  4. Rebuild and recompile any applications that link against the PolarSSL library
  5. Verify the new version is loaded by checking library version information at runtime
  6. Ensure any custom HAVEGE configuration is removed as the new version uses improved RNG mechanisms
Caveat Minimal expected - the primary change is the RNG replacement; verify any custom entropy configuration works with the new version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Polarssl Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA3.0 h
20.0 hours of engineering $3,420
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2011-4574 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data