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FrontendApplication · Zabbix

CVE-2025-49643

MEDIUM · 6.5 CVSS v3.1 Published 2025-12-01
Fix available
A fix is available. Upgrade to 6.0.42 / 7.0.19 or later.
See remediation →
71/100
Remediation priority · Elevated
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
An authenticated Zabbix user (including Guest) is able to cause disproportionate CPU load on the webserver by sending specially crafted parameters to /imgstore.php, leading to potential denial of service.

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

Zabbix versions prior to the fix allow authenticated users (including Guest) to send specially crafted parameters to /imgstore.php, causing disproportionate CPU consumption on the webserver. This results in potential denial of service due to resource exhaustion.

MitigationApply vendor-supplied patch or upgrade to a fixed Zabbix version. Alternatively, restrict access to /imgstore.php via web server configuration or disable the Guest account if not required.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FrontendApplication
Affected:>= 6.0.0, < 6.0.42>= 7.0.0, < 7.0.19>= 7.2.0, < 7.2.13>= 7.4.0, < 7.4.3

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
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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 Zabbix frontend installation
    Locate the Zabbix web files on the server. Check common paths such as /usr/share/zabbix, /var/www/html/zabbix, or the web root directory configured in your web server (Apache/Nginx). Look for the presence of imgstore.php in the frontent directory.
    Affected if The file imgstore.php exists in the Zabbix web directory and the installed Zabbix version falls within the affected ranges.
  2. Determine installed Zabbix version
    Check the VERSION file in the Zabbix web directory, or access the Zabbix web interface and look at the footer for the version number. Alternatively, check the Zabbix server version via 'zabbix_server -V' or check the packages installed on the system (rpm -qa | grep zabbix or dpkg -l | grep zabbix).
    Affected if The installed version is prior to 6.0.42, 7.0.19, 7.2.13, or 7.4.3 (specific to your branch).
  3. Verify Guest account is enabled
    Log into the Zabbix web interface as an administrator, navigate to Users > Users > Guest (or Users > User groups with Guest group), or query the database directly: SELECT * FROM users WHERE alias='guest' AND def_lang IS NOT NULL; Check if the Guest user is enabled (status = 0).
    Affected if The Guest account is enabled and usable for authentication.
  4. Confirm web server accessibility
    Verify that the Zabbix web interface is accessible over the network. Check if /imgstore.php is reachable from untrusted networks. Review web server access logs for requests to imgstore.php.
    Affected if The Zabbix frontend is exposed to untrusted networks and the affected version is running.

You are affected if Zabbix frontend version is prior to the fixed versions AND the web interface (including /imgstore.php) is accessible to authenticated users, including the Guest account.

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.

dbcve · scoped
Upgrade available Upgrade to 6.0.42 / 7.0.19 / 7.2.13 or later
Fixed in 6.0.427.0.197.2.13
Interim mitigation

Apply vendor-supplied patch or upgrade to a fixed Zabbix version. Alternatively, restrict access to /imgstore.php via web server configuration or disable the Guest account if not required.

Recommended fix High confidence

Upgrade to one of: Zabbix Frontend 6.0.42, 7.0.19, 7.2.13, or 7.4.3 (choose the branch matching your current major.minor version)

  1. 1. Identify the current Zabbix Frontend version by checking the dashboard or the file /includes/version.php
  2. 2. Determine which upgrade path applies based on current version (6.0.x, 7.0.x, 7.2.x, or 7.4.x)
  3. 3. Download the corresponding fixed release from https://www.zabbix.com/download_sources
  4. 4. Backup the current Zabbix Frontend installation directory and database
  5. 5. Extract the new version files, replacing the old frontend files
  6. 6. Verify the upgrade by logging into the Zabbix Frontend and checking the version number in the dashboard
  7. 7. Test that the /imgstore.php endpoint no longer accepts the specially crafted parameters that caused CPU exhaustion
Caveat Minor version upgrades typically have minimal breaking changes; however, always review the release notes for any backward-incompatible changes before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Frontend Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.

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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-2025-49643 in production — separate from our analysis above.

No notes yet

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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
  • No spam, self-promotion, credentials, or personal data