CVE-2021-43833
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 · uneditedeLabFTW is an electronic lab notebook manager for research teams. In versions prior to 4.2.0 there is a vulnerability which allows any authenticated user to gain access to arbitrary accounts by setting a specially crafted email address. This vulnerability impacts all instances that have not set an explicit email domain name allowlist. Note that whereas neither administrators nor targeted users are notified of a change, an attacker will need to control an account. The default settings require administrators to validate newly created accounts. The problem has been patched. Users should upgrade to at least version 4.2.0. For users unable to upgrade enabling an email domain allow list (from Sysconfig panel, Security tab) will completely resolve the issue.
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 confidenceAn access control bypass vulnerability in eLabFTW versions prior to 4.2.0 allows any authenticated user to take over arbitrary accounts by setting a specially crafted email address, exploiting the lack of email domain allowlist validation in the default configuration.
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< 4.2.0CVSS 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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Determine installed eLabFTW versionLog into eLabFTW as an administrator and navigate to the Admin panel > Info page, or check the VERSION file in the installation directory if you have filesystem access.Affected if The version shown is less than 4.2.0 (e.g., 4.0.0, 4.1.x, etc.)
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Verify email domain allowlist configurationLog into eLabFTW as an administrator and go to Sysconfig > Security tab. Look for the setting 'Allowed email domains' or similar domain allowlist option.Affected if The email domain allowlist is empty, disabled, or not configured (default configuration).
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Check configuration file directlyIf you have filesystem access, examine the eLabFTW configuration file (usually sysadmin.yml or config.yml in the config directory) for any email domain restrictions.Affected if No email domain restrictions are defined in the configuration file.
Your environment is affected if eLabFTW version is below 4.2.0 AND the email domain allowlist is not enabled or configured in Sysconfig > Security.
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 · scoped4.2.0
Upgrade to version 4.2.0 or later, or enable an email domain allowlist in Sysconfig > Security to restrict which email domains can register.
4.2.0 or later
- Plan and schedule the upgrade during a maintenance window
- Backup the current eLabFTW database and configuration files
- Upgrade eLabFTW to version 4.2.0 or later by following the official upgrade documentation
- After upgrade, verify that the authentication mechanism is working correctly
- Confirm that newly created accounts still require administrator validation (default setting)
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-43833 — 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-2021-43833 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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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.
- 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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