CVE-2021-21511
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 · uneditedDell EMC Avamar Server, versions 19.3 and 19.4 contain an Improper Authorization vulnerability in the web UI. A remote low privileged attacker could potentially exploit this vulnerability, to gain unauthorized read or modification access to other users' backup data.
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 · moderate confidenceDell EMC Avamar Server versions 19.3 and 19.4 contain an improper authorization vulnerability in the web UI where low-privileged remote attackers can bypass authorization checks to read or modify other users' backup data, indicating broken access control between users.
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= 19.3= 19.4= 2.6CVSS 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
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
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 Dell EMC Avamar Server versionCheck the installed Avamar Server version through the management interface or system information utility. Common methods include accessing the Avamar Administration console or using the 'avamar' CLI tool with version query flags.Affected if The installed version equals 19.3 or 19.4.
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Identify Dell EMC Integrated Data Protection Appliance versionCheck the IDPA version through its management console or system information interface.Affected if The installed IDPA version equals 2.6.
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Verify web UI is accessibleConfirm that the Avamar web UI (typically accessed via HTTPS on the management node) is currently enabled and reachable on the network.Affected if The web UI is exposed and accessible to network users.
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Confirm low-privilege user accounts existReview user accounts in the Avamar system to verify that low-privileged (non-administrator) user accounts are configured for backup operations.Affected if Low-privilege user accounts exist in the system.
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Assess network exposure of management interfaceDetermine whether the Avamar web management interface is reachable from network segments accessible to untrusted users, including direct IP access or through any reverse proxies.Affected if The web UI is accessible from untrusted network locations.
A user is affected if their installed Avamar Server version is 19.3 or 19.4 (or IDPA version 2.6), the web UI is enabled, and low-privileged users can access the management interface, as the authorization bypass allows such users to read or modify other users' backup data.
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.
From vendor dataApply vendor-provided security patches for Avamar Server 19.3/19.4 or upgrade to a patched version; implement and verify proper session validation and authorization checks for all web UI operations accessing user data.
- Consultation4.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,520.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-21511 — 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-2021-21511 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
- No spam, self-promotion, credentials, or personal data