dbcve.org
Improper Input ValidationWeakness · CWE-20

CVE-2026-13602

HIGH · 7.7 CVSS v4.0 Published 2026-07-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
83/100
Remediation priority · High
Remotely reachable Zero-click 8 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
We found a chain of combining multiple weaknesses in the product that could allow an attacker to become any user in the backend and access any data: * The payment integration plugins Stripe (included in the core system), pretix-mollie, pretix-oppwa, pretix-bitpay, pretix-payone, pretix-secuconnect, pretix-sofort, and pretix-saferpay contain a code path that is intended for the transport of session parameters from a tab with isolated cookies (e.g. in the pretix widget) to a new tab. For this purpose, a set of session parameters is cryptographically signed and then passed to the new tab as a URL parameter. The plugins perform no further validation of the session parameters, other than the cryptographic signature being valid. This is fixed with the releases issued today by strictly validating that no session parameters outside of the scope of the respective plugin may be set. * An unrelated feature in the core system is used to generate redirect links that obfuscate any Referer headers for outgoing links to prevent leakage of secrets in URLs. This redirect page also requires cryptographically signed parameters. Unfortunately, it uses the same key and salt for the signature as the previously mentioned feature in the payment integration plugins. A motivated attacker with access to at least one event in the backend can trick the system into cryptographically signing arbitrary content using specially crafted links. In combination with the previous issue, the attacker could use this to set and modify arbitrary parameters on their user session by injecting the signed parameters into the feature of the payment providers. This is fixed with the releases issued today by using different salts for the signature for each plugin and feature. * A third, unrelated feature in the core system is used for admin users to act on behalf of another user, mostly for debugging purposes. With being able to insert arbitrary parameters into a session, an attacker can abuse this feature to change their session from their actual user to any user in the system by guessing a valid user ID. This is fixed with the release today by requiring unguessable information to be contained in the session of the user to switch to.

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

A cryptographic signature bypass in payment integration plugins combined with key reuse in a core redirect feature allows attackers with backend event access to inject arbitrary session parameters via URL. This enables abuse of an admin impersonation feature to take over any user account by guessing valid user IDs.

MitigationApply vendor releases immediately: update all affected payment plugins to validate session parameters, ensure cryptographic salts differ per plugin/feature, and verify the admin impersonation feature now requires unguessable session information.

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
Low
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:U/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. Identify payment integration plugins
    Enumerate all installed payment plugins/modules in the application. Look for plugins that handle payment processing, subscription management, or financial transactions. Check plugin directories and configuration files for payment-related extensions.
    Affected if Payment integration plugins are installed and the cryptographic validation of session parameters is not enforced by those plugins.
  2. Inspect cryptographic key configuration
    Examine the application's configuration files for cryptographic keys, salts, or secrets used by payment plugins and the core redirect feature. Compare key values across different plugins and core components to identify key reuse patterns.
    Affected if The same cryptographic key or salt is shared between payment plugins and the core redirect feature, enabling signature bypass.
  3. Verify admin impersonation feature settings
    Locate and inspect the admin impersonation feature configuration. Check if it requires cryptographically unguessable session tokens, one-time codes, or other unpredictable session information before allowing impersonation.
    Affected if The admin impersonation feature relies on predictable or user-controllable session parameters that can be guessed or manipulated.
  4. Review URL parameter handling for session injection
    Test or inspect how the application handles session parameters passed via URL. Look for redirect endpoints that accept session-related parameters and verify if these can be manipulated without proper validation.
    Affected if The application allows injection of arbitrary session parameters through URL query parameters without cryptographic validation.
  5. Assess backend event access controls
    Review access controls for backend administrative interfaces, event logging systems, or administrative APIs. Determine if unprivileged users can access event data that may contain session information.
    Affected if Unprivileged users have access to backend event information that could reveal session tokens or other sensitive data used in the impersonation flow.

A user is affected if their environment has payment integration plugins installed with shared cryptographic keys and an admin impersonation feature that relies on guessable or user-injectable session parameters.

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

Apply vendor releases immediately: update all affected payment plugins to validate session parameters, ensure cryptographic salts differ per plugin/feature, and verify the admin impersonation feature now requires unguessable session information.

Have this fixed Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,580
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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-2026-13602 in production — separate from our analysis above.

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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
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