CVE-2026-40471
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 · uneditedhackage-server lacked Cross-Site Request Forgery (CSRF) protection across its endpoints. Scripts on foreign sites could trigger requests to hackage server, possibly abusing latent credentials to upload packages or perform other administrative actions. Some unauthenticated actions could also be abused (e.g. creating new user accounts).
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 confidencehackage-server, the Haskell package repository server, lacked Cross-Site Request Forgery (CSRF) protection across all its HTTP endpoints. This allowed malicious websites to trick authenticated users' browsers into sending unintended requests to hackage-server, potentially exploiting stored credentials to upload packages, perform administrative actions, or abuse unauthenticated endpoints like user registration.
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
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:L
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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Confirm hackage-server is runningIdentify the hackage-server process or check if port 8080 (default) is listening. Look for the hackage-server process using 'ps aux | grep hackage' or check open ports with 'netstat -tlnp'.Affected if hackage-server is not running (not applicable - only relevant if present)
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Check for CSRF token presence in HTTP responsesMake an authenticated request to a state-changing endpoint (e.g., package upload or user admin page) and inspect the response headers and HTML form fields. Look for anti-CSRF tokens in hidden form fields or custom headers. Use 'curl -v <endpoint>' to capture full response details.Affected if No anti-CSRF tokens appear in the response HTML or headers - the server does not implement CSRF protection
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Verify SameSite cookie attribute configurationLog in to hackage-server and capture the Set-Cookie headers in the response. Examine the session cookie for the 'SameSite' attribute using browser dev tools or 'curl -vD -' when authenticating.Affected if The session cookie lacks a SameSite attribute or has SameSite=None without Secure flag, indicating missing CSRF protection
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Test state-changing endpoint for CSRF vulnerabilityCreate a crafted HTML page that submits a request to a hackage-server endpoint (e.g., package upload) without a CSRF token, and attempt to trigger it from a different origin. Alternatively, use Burp Suite or similar to replay a request without anti-CSRF tokens to state-changing endpoints.Affected if The request succeeds without requiring a CSRF token, confirming the endpoint lacks CSRF protection
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Inspect server source code for CSRF middlewareIf access to the hackage-server source is available, search for CSRF-related middleware or token validation logic. Look for packages like 'websockets' or 'scotty' that may provide CSRF utilities, and check if they are applied to routes.Affected if No CSRF middleware or token validation logic is found in the server configuration or route handlers
A hackage-server instance is affected if it lacks anti-CSRF tokens in responses, does not set SameSite cookies, and permits state-changing operations without CSRF token validation.
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 dataImplement CSRF protection by adding anti-CSRF tokens to state-changing operations and validating them server-side, along with setting SameSite cookie attributes to prevent cross-origin requests.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,968.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-40471 — 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-2026-40471 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