CVE-2026-18754
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 product firmware contains an embedded, static RSA private key utilized by the Lighttpd web server for TLS termination. Exposure of this private key allows malicious actors to breach the confidentiality and integrity of HTTPS communications, enabling traffic decryption and server spoofing.
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 confidenceThe affected device firmware ships with a hardcoded RSA private key embedded in the Lighttpd web server binary/configuration. This static key is used for TLS termination on HTTPS connections. Anyone with knowledge of this key can decrypt captured TLS traffic or perform man-in-the-middle attacks by spoofing the server.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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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Locate Lighttpd configuration filesSearch for lighttpd.conf and related configuration files in the firmware image or running system (e.g., /etc/lighttpd/, /opt/etc/lighttpd/, or firmware extraction directories). Identify any .key or .pem files referenced in the config.Affected if A .key or .pem file containing an RSA private key is statically referenced in the Lighttpd configuration and that key is identical across multiple device instances.
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Inspect embedded private keys in configExamine the Lighttpd configuration for the ssl.pemfile or ssl.privkey directive. If the value is an inline PEM string or points to a file that contains the same key across different devices, extract and examine the key header (-----BEGIN RSA PRIVATE KEY----- or -----BEGIN PRIVATE KEY-----).Affected if The Lighttpd TLS configuration contains an embedded RSA private key that is hardcoded (not uniquely generated per device).
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Compare private keys across multiple devicesIf you have access to multiple devices running the same firmware version, extract the private key from each and compare them. Use commands like 'openssl rsa -in key.pem -modulus -noout' to compare the modulus.Affected if Multiple devices share the exact same RSA private key, indicating a hardcoded key.
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Check firmware for static private key filesExtract the firmware and search for files containing 'BEGIN RSA PRIVATE KEY' or 'BEGIN PRIVATE KEY' headers using 'strings' or binwalk. Look in common web server directories within the firmware.Affected if The firmware image contains an embedded RSA private key file that is statically compiled or stored in the filesystem.
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Verify key age and fingerprintIf a private key is found, check its modulus and creation date using 'openssl rsa -in key.pem -text -noout' and compare against known compromised key patterns if available.Affected if The private key was generated or embedded at firmware build time rather than during device initialization.
Your environment is affected if the Lighttpd web server in your device firmware uses a statically embedded RSA private key that is shared across multiple devices, rather than a unique per-device key.
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 dataReplace the embedded private key with a newly generated key pair, obtain and install a new certificate from a trusted CA, update the firmware with the new keys, and rotate any keys that may have been compromised using the exposed private key.
- Consultation3.0 h
- Implementation6.0 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-2026-18754 — 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-2026-18754 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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