CVE-2021-46145
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 keyfob subsystem in Honda Civic 2012 vehicles allows a replay attack for unlocking. This is related to a non-expiring rolling code and counter resynchronization.
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 confidenceThe keyfob subsystem in Honda Civic 2012 vehicles uses a rolling code mechanism for remote unlock that can be exploited via replay attack. The vulnerability stems from the rolling code not expiring and issues with counter resynchronization between the keyfob and vehicle, allowing an attacker to capture and reuse a previously transmitted unlock signal.
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
- Adjacent
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:A/AC:H/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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Confirm vehicle model and yearLocate the vehicle identification number (VIN) on the registration, insurance card, or driver's side dashboard. Check if the model is Honda Civic and the year is 2012.Affected if The vehicle is a Honda Civic from model year 2012.
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Identify keyfob hardware versionExamine the keyfob remote for any version markings or labels. Check Honda dealer records or keyfob packaging for model/part number information.Affected if The keyfob is the original equipment supplied with the 2012 Honda Civic and has not been replaced with an updated model.
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Verify rolling code is activeTest that the keyfob uses a rolling code mechanism by pressing unlock multiple times and observing that each press generates a new code (the vehicle should not respond to repeated identical signals).Affected if The rolling code mechanism is functioning as the primary unlock authentication (which is the default and cannot be disabled on affected vehicles).
A user is affected if they own a Honda Civic 2012 with the original keyfob that uses rolling code authentication, as the vulnerability is inherent to the rolling code design and cannot be mitigated through configuration changes.
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 dataContact Honda dealer or OEM for available security updates; if no patch exists, consider replacing the keyfob with an updated model or implementing additional physical security measures. Users should be advised of the limited risk scope (unlocking only, not starting the vehicle).
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA6.0 h
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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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-46145 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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