Enterprise LinuxOperating system · Redhat
CVE-2018-10184
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 · uneditedAn issue was discovered in HAProxy before 1.8.8. The incoming H2 frame length was checked against the max_frame_size setting instead of being checked against the bufsize. The max_frame_size only applies to outgoing traffic and not to incoming, so if a large enough frame size is advertised in the SETTINGS frame, a wrapped frame will be defragmented into a temporary allocated buffer where the second fragment may overflow the heap by up to 16 kB. It is very unlikely that this can be exploited for code execution given that buffers are very short lived and their addresses not realistically predictable in production, but the likelihood of an immediate crash is absolutely certain.
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 confidenceIn HAProxy before 1.8.8, incoming H2 frame length is incorrectly validated against the max_frame_size setting (which only applies to outgoing traffic) instead of the bufsize. When a large frame size is advertised in the SETTINGS frame, defragmentation of wrapped frames into a temporary buffer allows the second fragment to overflow the heap by up to 16 kB, causing likely crashes though code execution is deemed unlikely.
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
Enterprise LinuxOperating system
= 7.0= 7.3= 7.4= 7.5< 1.8.8CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Identify HAProxy versionRun 'haproxy -v' or 'haproxy --version' to get the installed version numberAffected if Version is earlier than 1.8.8
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Check if H2 protocol support is enabledInspect HAProxy configuration files (typically /etc/haproxy/haproxy.cfg) for 'bind' directives containing 'alpn h2' or 'proto h2', or 'http2' mode settings in the frontend or backend sectionsAffected if H2 (HTTP/2) protocol is enabled via configuration
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Verify the bufsize setting in configurationLook for 'bufsize' parameter in the global section of HAProxy config. If not set, the default is used. This setting determines the buffer size for incoming frame handlingAffected if bufsize is configured (this determines the actual heap overflow magnitude)
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Confirm HAProxy is accepting H2 connectionsReview listen or frontend sections for ports configured to accept HTTP/2 traffic (typically ports 443, 8443, or custom ports with H2 enabled)Affected if HAProxy is listening on ports that accept H2 connections
You are affected if HAProxy version is earlier than 1.8.8 AND H2 protocol support is enabled in the configuration, because the vulnerability only triggers when processing incoming H2 frames
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 data1.8.8
Upgrade HAProxy to version 1.8.8 or later to obtain the patch that correctly validates incoming H2 frame lengths against bufsize instead of max_frame_size.
Fix this in Enterprise Linux
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-10184 — 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-2018-10184 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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- Version or environment caveats, and links to real fixes
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