dbcve.org
CWE-346Weakness · CWE-346

CVE-2026-52843

CRITICAL · 9.3 CVSS v3.1 Published 2026-07-15
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Patch available 6 weeks old

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 · unedited
Lightpanda is a headless browser designed for AI and automation. Prior to 0.2.9, Lightpanda fetch() and XMLHttpRequest unconditionally attached session cookies to every HTTP request, ignoring credentials: omit, credentials: same-origin, credentials: include, and XMLHttpRequest.withCredentials, allowing an attacker-controlled origin in a Lightpanda session to issue authenticated cross-origin requests against a victim origin. This issue is fixed in version 0.2.9.

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 confidence

Lightpanda headless browser prior to 0.2.9 unconditionally attaches session cookies to all HTTP requests made via fetch() and XMLHttpRequest, ignoring the standard credentials options (omit, same-origin, include) and XMLHttpRequest.withCredentials. This allows any origin with code execution in a Lightpanda session to make authenticated cross-origin requests against victim domains.

MitigationUpgrade Lightpanda to version 0.2.9 or later. If upgrading is not immediately possible, audit any Lightpanda deployments to ensure untrusted origins cannot execute code within the session.

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify Lightpanda installation
    Locate the Lightpanda binary or package in your environment. Check common paths such as /usr/local/bin/lightpanda, ~/.npm-global/bin/lightpanda, or use 'which lightpanda' on Linux/macOS or 'where lightpanda' on Windows. If installed via npm, run 'npm list -g lightpanda' or check your package-lock.json for a lightpanda dependency.
    Affected if Lightpanda headless browser is found installed in the environment
  2. Determine installed version
    Run the command 'lightpanda --version' if the binary is available, or check the version from your package manager (e.g., npm list lightpanda, cargo list lightpanda depending on how it was installed). Compare the version number against the affected range of versions prior to 0.2.9.
    Affected if The installed version is below 0.2.9
  3. Verify fetch or XMLHttpRequest usage
    Audit your codebase or any automated scripts that run within Lightpanda sessions. Search for occurrences of fetch() calls or XMLHttpRequest object usage that make HTTP requests. Determine whether these requests target cross-origin URLs (domains different from the page origin).
    Affected if Your Lightpanda-based code uses fetch() or XMLHttpRequest to make requests to external/origin domains and the version is below 0.2.9
  4. Test credentials handling behavior
    If the above conditions are met, create a test page within Lightpanda that makes a fetch() request with credentials: 'omit' or an XMLHttpRequest with withCredentials=false to a cross-origin URL, then inspect the outgoing request headers to confirm whether session cookies are still being sent despite these settings.
    Affected if Session cookies are attached to requests even when credentials options are explicitly set to omit or withCredentials is set to false, confirming the vulnerable behavior is present

You are affected if Lightpanda version 0.2.9 or earlier is installed and your application or scripts use fetch() or XMLHttpRequest to make cross-origin HTTP requests within a Lightpanda session.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Patch available Apply the vendor patch
Vendor patch github.com →
Interim mitigation

Upgrade Lightpanda to version 0.2.9 or later. If upgrading is not immediately possible, audit any Lightpanda deployments to ensure untrusted origins cannot execute code within the session.

Recommended fix High confidence

0.2.9

  1. 1. Identify the current Lightpanda version in use by checking package.json, Cargo.toml, or the installed binary version
  2. 2. If using a package manager (npm, cargo, etc.), update to version 0.2.9 or later: npm install lightpanda@latest or cargo update lightpanda
  3. 3. If using a pre-built binary, download version 0.2.9 or later from the official GitHub releases page
  4. 4. Verify the upgrade was successful by checking the installed version matches 0.2.9 or higher
  5. 5. Test that fetch() and XMLHttpRequest now respect the credentials options (omit, same-origin, include) as expected

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
Get the patch applied

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-52843 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-52843 in production — separate from our analysis above.

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.

What this is

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.

What belongs here
  • 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