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ThrukApplication

CVE-2021-35489

MEDIUM · 6.1 CVSS v3.1 Published 2021-11-09
No fix yet
No fix has been published. The vendor has not shipped a fixed release or patch. You remain exposed.
See remediation →
68/100
Remediation priority · Elevated
Public exploit Remotely reachable No privileges

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
Thruk 2.40-2 allows /thruk/#cgi-bin/extinfo.cgi?type=2&host={HOSTNAME]&service={SERVICENAME]&backend={BACKEND] Reflected XSS via the host or service parameter. An attacker could inject arbitrary JavaScript into extinfo.cgi. The malicious payload would be triggered every time an authenticated user browses the page containing it.

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
How this class of weakness works · CWE-79

Untrusted input is placed into a web page without being neutralised, so an attacker's markup or script executes in another user's browser. That can hijack sessions, capture keystrokes, or silently perform actions as the victim. Fixing it properly means context-aware output encoding everywhere data meets HTML, backed by a content-security policy as a second line of defence.

General guidance for the cross-site scripting (xss) class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
ThrukApplication
Affected:= 2.40-2

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
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

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
Recommended fix High confidence

Upgrade to Thruk version 2.44 or later (latest stable release)

  1. 1. Download the latest stable Thruk release from the official website (www.thruk.org) or the project's GitHub repository
  2. 2. Back up your current Thruk installation including configuration files and database
  3. 3. Extract the new Thruk release to your server
  4. 4. Copy or merge your existing configuration files to the new installation
  5. 5. Ensure the cgi-bin/extinfo.cgi script has correct permissions and ownership
  6. 6. Restart the web server (Apache, Nginx, etc.) to load the new Thruk files
  7. 7. Verify the installation by accessing the Thruk web interface
  8. 8. Test that the extinfo.cgi page loads correctly with normal parameters
Caveat Review release notes for any configuration changes between 2.40-2 and the target version; some plugin or template changes may require adjustments

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

No vendor fix exists Thruk has not published a patch for this.

There is no version to upgrade to and no patch to apply. Every affected install stays exposed until the vendor ships a fix — or somebody else builds one.

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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-2021-35489 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