CVE-2026-58656
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 · uneditedGrav API plugin before v1.0.0-rc.16 accepts JWT tokens via the ?token= URL query parameter and responds with Access-Control-Allow-Origin: *, allowing unauthenticated attackers to make fully authenticated cross-origin API requests from any malicious website. Attackers who obtain a leaked JWT token from access logs, proxy logs, browser history, or Referrer headers can create persistent backdoor super-admin accounts and exfiltrate sensitive configuration and user data.
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 Grav API plugin before v1.0.0-rc.16 passes JWT tokens through the URL query parameter (?token=), which exposes tokens in server logs, browser history, and Referrer headers. Combined with an overly permissive Access-Control-Allow-Origin: * header, this allows any malicious website to silently make authenticated API requests on behalf of a victim who has previously used the API. Attackers can then create backdoor super-admin accounts and steal sensitive data.
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
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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.
-
Confirm Grav CMS and API plugin installationIdentify if Grav CMS is running and locate the Grav API plugin. Check for the presence of the 'grav-plugin-api' or similar plugin directory within the Grav installation.Affected if The Grav API plugin is installed on the system.
-
Check the installed API plugin versionInspect the plugin's version file (typically version.php or composer.json within the plugin directory) or query the plugin through Grav's admin interface if available. Compare the version against the affected range: versions before v1.0.0-rc.16.Affected if The installed version is before v1.0.0-rc.16.
-
Inspect JWT token transmission configurationExamine the plugin's configuration file (usually config.yaml or similar in the plugin directory) for settings related to token transmission. Look for configuration that passes JWT tokens via URL query parameters (?token=) rather than HTTP headers.Affected if The plugin is configured to transmit JWT tokens through URL query parameters.
-
Review CORS policy configurationCheck the plugin's configuration for Access-Control-Allow-Origin settings. Inspect HTTP response headers from API requests or review the plugin source code for CORS header generation.Affected if The Access-Control-Allow-Origin header is set to wildcard (*).
The environment is affected if the Grav API plugin is installed with a version before v1.0.0-rc.16 and is configured to pass JWT tokens via URL query parameters with a permissive CORS policy.
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 dataUpgrade to Grav API plugin v1.0.0-rc.16 or later, which should address the JWT token exposure and implement proper CORS origin validation instead of wildcard policies.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-58656 — 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-2026-58656 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
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.
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.
- 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