CVE-2021-33186
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 · uneditedSerenityOS in test-crypto.cpp contains a stack buffer overflow which could allow attackers to obtain sensitive information.
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 confidenceSerenityOS contains a stack buffer overflow vulnerability in test-crypto.cpp, a test file for cryptographic functionality. The overflow could allow attackers to read sensitive information from the stack, potentially exposing cryptographic keys or other confidential data.
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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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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Locate test-crypto.cpp in the source treeSearch the SerenityOS source directory for test-crypto.cpp using 'find . -name test-crypto.cpp' or similar file search commandsAffected if The file exists in the source tree and was compiled into the deployed binary image
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Identify if test-crypto.cpp was compiled into production buildsCheck the build configuration and output binaries for symbols or code from test-crypto.cpp. Look for test-crypto related symbols in the compiled kernel or userspace binaries using 'strings' or binary analysis toolsAffected if Test code from test-crypto.cpp is present in the production binary
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Verify if cryptographic test functionality is accessible in productionInspect the deployed binary to determine if the test_crypto function or related test routines are exported and callable. Check for entry points that invoke the vulnerable test codeAffected if The test crypto functionality is exposed and executable in the production environment
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Determine if the build includes debug or test symbolsReview the build configuration to confirm whether DEBUG or TEST build flags were used, which would typically include test files in production binariesAffected if The binary was built with test or debug features enabled
The environment is affected if test-crypto.cpp or its compiled code is present in the production build and the cryptographic test functionality is accessible for execution.
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 dataEnsure test-crypto.cpp is not included in production builds, or apply proper bounds checking to all stack buffer operations in the affected file before deploying.
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-33186 — 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-2021-33186 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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