CVE-2012-3291
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 · uneditedHeap-based buffer overflow in OpenConnect 3.18 allows remote servers to cause a denial of service via a crafted greeting banner.
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 confidenceHeap-based buffer overflow in OpenConnect version 3.18 in the code that parses incoming server greeting banners. When a remote server sends a specially crafted oversized greeting banner, the application fails to properly bounds-check the input before copying it into a heap-allocated buffer, leading to heap corruption and denial of service.
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<= 3.17= 1.00= 1.10= 1.20= 1.30= 1.40= 2.00= 2.01= 2.10= 2.11= 2.12= 2.20CVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Complete
AV:N/AC:L/Au:N/C:N/I:N/A:C
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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Identify OpenConnect versionRun 'openconnect --version' or check the installed package version via package manager (dpkg -l openconnect, rpm -qi openconnect)Affected if Version is 3.18 (where vulnerability exists in banner parsing code) or <= 3.17, or one of: 1.00, 1.10, 1.20, 1.30, 1.40, 2.00, 2.01, 2.10, 2.11, 2.12, 2.20
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Verify VPN client mode is in useConfirm OpenConnect is configured to connect to a VPN server using the openconnect command-line clientAffected if OpenConnect client is actively being used to establish VPN connections where it receives server greeting banners
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Confirm network connectivity to VPN serversCheck if outbound connections to VPN servers are allowed (iptables -L OUTPUT, firewall-cmd --list-services)Affected if The client can connect to remote VPN servers that would send greeting banners during handshake
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Audit server greeting banner handling (if logs accessible)Review OpenConnect debug logs or verbose output (-v flag) for incoming banner handling during connection attemptsAffected if Banners are being received and processed without truncation or validation
User is affected if running a vulnerable OpenConnect version (3.18 or <= 3.17, or listed affected point releases) and using the client to connect to VPN servers that transmit greeting banners during the handshake.
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 OpenConnect to a version newer than 3.18 that includes proper bounds-checking for server greeting banners, or apply the vendor-supplied patch if backporting is required.
- Consultation2.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2012-3291 — 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-2012-3291 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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