CVE-2023-40518
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 · uneditedLiteSpeed OpenLiteSpeed before 1.7.18 does not strictly validate HTTP request headers.
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 confidenceLiteSpeed OpenLiteSpeed versions prior to 1.7.18 fail to properly validate HTTP request headers, potentially allowing attackers to inject malicious headers or bypass security controls through malformed requests.
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< 1.7.18CVSS 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
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/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.
-
Identify OpenLiteSpeed installationRun 'openlitespeed -v' or check the web admin interface (usually port 7080) for the server version informationAffected if The version displayed is less than 1.7.18
-
Check package manager versionIf installed via package manager (apt, yum, dnf), run 'rpm -qa | grep openlitespeed' or 'dpkg -l | grep openlitespeed' to retrieve the installed package versionAffected if The package version shown is earlier than 1.7.18
-
Verify HTTP header processing is activeConfirm the OpenLiteSpeed service is running and actively processing HTTP/HTTPS requests on ports 80/443 or custom portsAffected if The server is running and processing requests while version is below 1.7.18
You are affected if OpenLiteSpeed is installed and running with a version lower than 1.7.18, as this version range contains the incomplete HTTP request header validation vulnerability.
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.
dbcve · scoped1.7.18
Upgrade LiteSpeed OpenLiteSpeed to version 1.7.18 or later to obtain the proper header validation fix.
1.7.18 or later (current stable release recommended)
- Download OpenLiteSpeed version 1.7.18 or later from the official LiteSpeed repositories or source
- Stop the OpenLiteSpeed service before upgrading
- Upgrade the OpenLiteSpeed package using your system's package manager (e.g., yum, apt, or rpm) or compile from source
- Verify the installation was successful by checking the version number
- Restart the OpenLiteSpeed service
- Test that web services are functioning normally
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 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 $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-40518 — 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-2023-40518 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data