CVE-2026-52842
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 · uneditedLightpanda is a headless browser designed for AI and automation. Prior to 0.3.1, Lightpanda searched for @ across the entire URL string instead of only the authority component when computing a page origin, so a URL such as `http://attacker.com/@victim.com/` was fetched from attacker.com but treated as `http://victim.com`, allowing a complete Same-Origin Policy bypass. This issue is fixed in version 0.3.1.
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 confidenceLightpanda headless browser had a URL origin computation flaw where it searched for the @ symbol across the entire URL string rather than limiting the search to the authority component. This caused URLs like http://attacker.com/@victim.com/ to be fetched from attacker.com but incorrectly assigned an origin of victim.com, completely bypassing Same-Origin Policy protections.
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
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/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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Verify Lightpanda installationCheck for the lightpanda binary in common locations such as /usr/bin/lightpanda, ~/.local/bin/lightpanda, or via command: which lightpandaAffected if Lightpanda binary is not found on the system, then this CVE does not apply
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Determine installed versionRun lightpanda --version to retrieve the installed version numberAffected if Version cannot be determined or command fails
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Compare version to fixed releaseCompare the installed version to 0.3.1. Parse the version string (e.g., 0.2.0, 0.3.0) and check if it is less than 0.3.1Affected if Installed version is 0.3.0 or earlier (versions prior to 0.3.1 contain the flaw)
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Inspect URL origin behavior (optional validation)If running a test environment, attempt to fetch a URL with the pattern http://attacker.com/@victim.com/ and inspect the computed origin header or origin property returned by the browserAffected if The origin is computed as victim.com instead of attacker.com, confirming the vulnerability is present
User is affected if Lightpanda headless browser is installed with a version lower than 0.3.1, as only those versions contain the flawed URL origin computation logic that searches for @ outside the authority component.
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 · scopedUpgrade Lightpanda to version 0.3.1 or later which fixes the URL parsing logic to only search for @ within the authority component when computing origin.
Upgrade to Lightpanda version 0.3.1 or later
- 1. Check the current installed version of Lightpanda by running the version command specific to the Lightpanda installation method
- 2. If the version is below 0.3.1, upgrade to version 0.3.1 or later
- 3. Verify the upgrade was successful by checking the new version
- 4. Test that URLs with @ in the path are now properly handled (e.g., http://attacker.com/@victim.com/ should NOT be treated as http://victim.com)
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-52842 — 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-2026-52842 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
- No spam, self-promotion, credentials, or personal data