dbcve.org
Improper Signature VerificationWeakness · CWE-347

CVE-2025-30064

HIGH · 8.8 CVSS v4.0 Published 2025-08-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
90/100
Remediation priority · Urgent
Zero-click

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
An insufficiently secured internal function allows session generation for arbitrary users. The decodeParam function checks the JWT but does not verify which signing algorithm was used. As a result, an attacker can use the "ex:action" parameter in the VerifyUserByThrustedService function to generate a session for any user.

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 · moderate confidence

This is a JWT algorithm confusion vulnerability where the decodeParam function validates the JWT signature but fails to verify which signing algorithm was used. An attacker can exploit the 'ex:action' parameter in the VerifyUserByThrustedService function to bypass authentication and generate sessions for arbitrary users by specifying a weak or no algorithm in the JWT.

MitigationImplement proper JWT algorithm verification in the decodeParam function to ensure only expected algorithms (e.g., HS256, RS256) are accepted, rejecting 'none' or algorithm switching attacks. Apply access controls to the VerifyUserByThrustedService function to prevent unauthorized session generation.

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
Local
Complexity
High
Privileges
Low
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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. Locate the decodeParam function in your codebase
    Search source code for 'decodeParam' function definition and review its implementation for JWT token parsing logic
    Affected if The function exists and processes JWT tokens without verifying the signing algorithm header
  2. Inspect JWT algorithm verification in decodeParam
    Examine the decodeParam code to see if it checks the 'alg' field in JWT headers - look for explicit whitelist of allowed algorithms (e.g., HMAC) before signature verification
    Affected if No algorithm verification exists or 'none' algorithm is accepted
  3. Check 'ex:action' parameter handling in VerifyUserByThrustedService
    Find the VerifyUserByThrustedService function and review how 'ex:action' parameter is processed - look for allowlist validation before creating sessions
    Affected if The 'ex:action' parameter is not validated against an allowlist or is used directly in session creation
  4. Verify JWT library configuration for algorithm restrictions
    Review JWT library configuration or initialization code to confirm only expected algorithms (e.g., HS256) are enabled and 'none' or asymmetric algorithms are explicitly disabled
    Affected if JWT library accepts multiple algorithms or 'none' is not explicitly rejected
  5. Compare your deployed version to vendor releases
    Check your installed software version against the version that contains the fix for this algorithm confusion vulnerability
    Affected if Your version is older than the patched release containing algorithm verification fixes

You are affected if your environment uses the vulnerable decodeParam function to process JWT tokens without verifying the signing algorithm and does not validate the 'ex:action' parameter in VerifyUserByThrustedService.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement proper JWT algorithm verification in the decodeParam function to ensure only expected algorithms (e.g., HS256, RS256) are accepted, rejecting 'none' or algorithm switching attacks. Apply access controls to the VerifyUserByThrustedService function to prevent unauthorized session generation.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA3.0 h
17.0 hours of engineering $3,020
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,832.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-30064 — 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-2025-30064 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