CVE-2020-37124
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 · uneditedB64dec 1.1.2 contains a buffer overflow vulnerability that allows attackers to execute arbitrary code by overwriting Structured Exception Handler (SEH) with crafted input. Attackers can leverage an egg hunter technique and carefully constructed payload to inject and execute malicious code during base64 decoding process.
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 confidenceB64dec 1.1.2 contains a buffer overflow vulnerability during base64 decoding that allows attackers to overwrite the Structured Exception Handler (SEH). By using an egg hunter technique with a carefully crafted payload, attackers can inject and execute arbitrary code on the affected system.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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 checksWork through these to decide whether this CVE applies to you.
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Locate B64dec installationSearch for the b64dec binary or library on the system using 'which b64dec', 'find / -name b64dec* 2>/dev/null', or check common installation directoriesAffected if b64dec is found on the system
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Determine installed versionRun 'b64dec --version' or 'b64dec -v' to retrieve the version numberAffected if version is 1.1.2 or earlier (the vulnerability exists in 1.1.2)
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Verify base64 decoding is in useReview application logs, processes, or configurations to confirm b64dec is actively used for base64 decoding operationsAffected if b64dec is installed and base64 decoding functionality is invoked
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Inspect for SEH corruption indicatorsIf b64dec has been run, check for crash logs, core dumps, or error reports containing SEH (Structured Exception Handler) overwrite patterns or buffer overflow signaturesAffected if crash dumps show SEH chain corruption or unexpected memory writes during decoding
The environment is affected if B64dec version 1.1.2 (or earlier) is installed and base64 decoding functionality is actively used, as the buffer overflow occurs during the decoding process.
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 dataUpgrade to a patched version if available. Otherwise, implement strict input validation with size limits on base64 input and refactor the decoder to use safe memory handling with proper bounds checking to prevent SEH overwrite.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 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 $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-37124 — 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-2020-37124 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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