CVE-2026-36727
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 · uneditedAn insecure authentication vulnerability in the /api/social-sign-in endpoint of bookcars v8.3 allows attackers to bypass authentication via a forged JWT token.
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 /api/social-sign-in endpoint in bookcars v8.3 performs insufficient validation of JWT tokens, allowing attackers to bypass authentication by presenting a forged JWT. The authentication logic fails to properly verify the token signature, expiration, claims, or other security properties that validate JWT authenticity.
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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Identify bookcars installation and versionLocate the bookcars application installation directory and check the package.json or version file to determine the installed version. Compare against v8.3 and any versions above or below it.Affected if The installed version is exactly v8.3 or falls within the affected version range around v8.3.
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Verify /api/social-sign-in endpoint existsCheck if the /api/social-sign-in route is defined in the application's routing configuration (typically in a routes or api definition file). Attempt a request to the endpoint to confirm it is accessible.Affected if The /api/social-sign-in endpoint is exposed and responds to requests.
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Inspect JWT implementation for this endpointLocate the code handling the /api/social-sign-in route. Examine the JWT verification logic in the authentication handler. Check whether the code calls a JWT validation function and inspect what validation steps are performed.Affected if The code does not perform signature verification, or the verify() function is called with an insecure or missing secret, or signature validation is bypassed entirely.
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Check for proper token claim validationReview the JWT validation code to determine if it verifies standard claims such as issuer (iss), audience (aud), and expiration (exp). Look for explicit claim validation logic before accepting the token.Affected if Token claims are not validated, or validation is missing entirely.
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Test endpoint with forged JWTCreate a JWT token with arbitrary claims (e.g., user ID, role) signed with a weak or known secret, or with no signature, and send it to the /api/social-sign-in endpoint to observe if authentication succeeds.Affected if The endpoint accepts and authenticates the forged token, granting access without proper signature verification.
A user is affected if they are running bookcars v8.3 (or an affected version) with the /api/social-sign-in endpoint exposed and the JWT signature validation is missing or improperly implemented for that endpoint.
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 proper JWT validation including cryptographic signature verification using a trusted secret/key, validation of issuer and audience claims, and verification of token expiration. Ensure all authentication-critical endpoints use consistent, robust JWT validation.
- 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-2026-36727 — 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-2026-36727 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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