CWE-1336Weakness · CWE-1336

CVE-2026-34906

CRITICAL · 9.3 CVSS v4.0 Published 2026-06-02
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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
Server-Side Template Injection (SSTI) in Wirtualna Uczelnia allows an unauthenticated attacker to perform Remote Code Execution (RCE). In the endpoint redirectToUrl and parameter redirectUrlParameter, insufficient input validation permits injection of arbitrary template expressions that are executed on the server. Successful exploitation can allow an attacker to run remote commands, including establishing a reverse shell. This issue affects Wirtualna Uczelnia versions up to wu#2016.437.295#0#20260327_105545

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

This is a Server-Side Template Injection (SSTI) vulnerability in Wirtualna Uczelnia's redirectToUrl endpoint where the redirectUrlParameter lacks proper input validation. Attackers can inject arbitrary template expressions that the server executes, enabling Remote Code Execution (RCE) and potentially reverse shell establishment.

MitigationImplement strict input validation on the redirectUrlParameter to reject any template syntax characters/expressions, or disable template evaluation for user-supplied input in that parameter. Update to a patched version when available.

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
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/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. Identify Wirtualna Uczelnia installation
    Locate the application binaries, configuration files, or web application root directory. Check for files or services associated with Wirtualna Uczelnia.
    Affected if Wirtualna Uczelnia software is present in the environment
  2. Verify redirectToUrl endpoint availability
    Identify the base URL for the Wirtualna Uczelnia web application and check if a redirectToUrl endpoint is accessible (e.g., /redirectToUrl, /redirect, or similar path).
    Affected if The redirectToUrl endpoint responds to requests (is exposed and enabled)
  3. Confirm redirectUrlParameter acceptance of template syntax
    Send a benign template expression test to the redirectUrlParameter (e.g., {{7*7}} or similar syntax depending on the template engine) and observe if the application evaluates and returns the computed result instead of treating it as a literal string.
    Affected if Template expressions in redirectUrlParameter are evaluated rather than treated as plain text

If Wirtualna Uczelnia is present, the redirectToUrl endpoint with redirectUrlParameter is exposed, and template expressions are being evaluated, the environment is affected by CVE-2026-34906.

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 strict input validation on the redirectUrlParameter to reject any template syntax characters/expressions, or disable template evaluation for user-supplied input in that parameter. Update to a patched version when available.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,290
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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-2026-34906 in production — separate from our analysis above.

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What this is

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What belongs here
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