dbcve.org
SQL InjectionWeakness · CWE-89

CVE-2026-23921

HIGH · 8.7 CVSS v4.0 Published 2026-03-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
93/100
Remediation priority · Urgent
Remotely reachable 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
A low privilege Zabbix user with API access can exploit a blind SQL injection vulnerability in include/classes/api/CApiService.php to execute arbitrary SQL selects via the sortfield parameter. Although query results are not returned directly, an attacker can exfiltrate arbitrary database data through time-based techniques, potentially leading to session identifier disclosure and administrator account compromise.

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 blind SQL injection vulnerability exists in Zabbix's API service (CApiService.php) via the sortfield parameter. An authenticated low-privilege user with API access can inject malicious SQL queries that execute but return no direct output. Attackers can use time-based techniques (e.g., sleep queries) to infer data and exfiltrate sensitive information such as session identifiers, potentially leading to administrative account compromise.

MitigationApply vendor patches for this vulnerability and implement strict input validation on the sortfield parameter to prevent SQL injection. Follow least-privilege principles for API users and rotate sessions immediately if compromise is suspected.

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:N/SI:N/SA:N/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. Confirm Zabbix installation
    Locate Zabbix components in your environment - check for web frontend directories (typically under /usr/share/zabbix or /var/www/html/zabbix), configuration files (zabbix.conf.php), and running processes (zabbix_server, zabbix_agentd).
    Affected if Zabbix software is present in the environment.
  2. Identify Zabbix version
    Check the version by reviewing the Zabbix frontend footer, querying the API endpoint /api/version, or inspecting the include/version.php file in the web directory.
    Affected if The installed version matches the vulnerable version range published in the Zabbix security advisory for CVE-2026-23921.
  3. Verify API service is enabled
    Confirm the Zabbix API is accessible by sending a GET request to http(s)://<zabbix-server>/api/. A valid JSON response indicates the API is enabled.
    Affected if The API endpoint responds and is reachable from your network.
  4. Check API access for low-privilege users
    Review Zabbix user permissions in Administration > Users > Users. Verify whether standard (non-admin) users have API access enabled under user media/settings.
    Affected if Low-privilege users (User type: Standard or higher) have API access permissions granted.
  5. Inspect sortfield parameter exposure
    If you have API access, attempt a test query to the API endpoint /api/jsrpc.php with a sortfield parameter containing a benign time-based payload (e.g., 1 AND 1=1 SLEEP(2)--) and measure response time. Use an authorized test account only.
    Affected if The sortfield parameter accepts unsanitized input and time delays are observed, indicating the injection point is vulnerable.

Your environment is affected if Zabbix is installed with a version within the vulnerable range, the API service is accessible, and low-privilege users have API access enabled allowing unsanitized sortfield parameter input.

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 patches for this vulnerability and implement strict input validation on the sortfield parameter to prevent SQL injection. Follow least-privilege principles for API users and rotate sessions immediately if compromise is suspected.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing5.0 h
  • Review / QA3.0 h
18.0 hours of engineering $3,170
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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-2026-23921 in production — separate from our analysis above.

No notes yet

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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