CVE-2021-42124
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 · uneditedAn improper access control vulnerability exists in Ivanti Avalanche before 6.3.3 allows an attacker with access to the Inforail Service to perform a session takeover.
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 confidenceIvanti Avalanche before version 6.3.3 contains an improper access control vulnerability in the Inforail Service that allows an authenticated attacker with access to that specific service component to perform session takeover, potentially hijacking other user sessions.
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< 6.3.3CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 checksWork through these to decide whether this CVE applies to you.
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Identify if Ivanti Avalanche is installedCheck the system for Ivanti Avalanche installation directories or use system inventory tools to list installed software packages containing 'Avalanche'Affected if Ivanti Avalanche is not found on the system, the vulnerability does not apply
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Determine the installed Ivanti Avalanche versionLocate and read the version information from the Avalanche installation, typically found in the application itself, about dialog, or installed programs listingAffected if The installed version is 6.3.3 or later, the vulnerability does not apply
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Verify the Inforail Service component statusCheck if the Inforail Service is installed and running as part of the Avalanche deploymentAffected if The Inforail Service is not present or not enabled, the vulnerability may not be exploitable
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Assess network exposure of the Inforail ServiceReview firewall rules, network configurations, and ACLs to determine if the Inforail Service port is accessible to untrusted network segmentsAffected if The Inforail Service is exposed to untrusted users, an authenticated attacker could potentially exploit the session takeover vulnerability
The environment is affected if Ivanti Avalanche is installed with a version before 6.3.3 and the Inforail Service component is accessible to potential attackers.
Generated from the published advisory. Verify against your own configuration.
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 · scoped6.3.3
Upgrade Ivanti Avalanche to version 6.3.3 or later. Additionally, restrict network access to the Inforail Service to trusted personnel only until the upgrade can be applied.
Ivanti Avalanche 6.3.3
- 1. Back up the current Ivanti Avalanche configuration and database
- 2. Download Ivanti Avalanche version 6.3.3 or later from the official Ivanti download portal
- 3. Stop the Avalanche server services
- 4. Install the updated Avalanche 6.3.3 package following standard upgrade procedures
- 5. Restart Avalanche services
- 6. Verify the Inforail Service is functioning correctly
- 7. Test that the session handling functions properly after the upgrade
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-42124 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-42124 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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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