CVE-2012-2942
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 · uneditedBuffer overflow in the trash buffer in the header capture functionality in HAProxy before 1.4.21, when global.tune.bufsize is set to a value greater than the default and header rewriting is enabled, allows remote attackers to cause a denial of service and possibly execute arbitrary code via unspecified vectors.
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 confidenceBuffer overflow in HAProxy's trash buffer within header capture functionality. Vulnerability触发s when global.tune.bufsize is set larger than default AND header rewriting is enabled, allowing remote attackers to cause denial of service and potentially execute arbitrary code.
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<= 1.4.20CVSS 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
- High
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:H/Au:N/C:P/I:P/A:P
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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Check installed HAProxy versionRun 'haproxy -v' or 'haproxy -V' to display version informationAffected if Version is 1.4.20 or earlier
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Locate HAProxy configuration fileCommon paths: /etc/haproxy/haproxy.cfg, /etc/haproxy.conf, or check 'haproxy -f' default locationAffected if Configuration file exists and contains HAProxy settings
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Check if global.tune.bufsize is set larger than defaultSearch config file for 'tune.bufsize' directive and note its value. Default is typically 16384 bytes. Look for values significantly larger than default.Affected if tune.bufsize is explicitly set to a value larger than the default (approximately > 16384)
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Check if header rewriting is enabledSearch config file for http-check rules with 'rewrite' or 'http-response set-header'/'http-request set-header' directives that manipulate headers. Also check for 'option httpchk' with custom rules.Affected if Any http-check rewrite rules or header manipulation directives are present in the configuration
System is affected if HAProxy version is 1.4.20 or earlier AND global.tune.bufsize is set larger than default AND header rewriting rules are configured
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 HAProxy 1.4.21 or later; alternatively, maintain default global.tune.bufsize value or disable header rewriting as temporary workaround until upgrade is possible.
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2012-2942 — 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-2012-2942 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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