How severe is CVE-2021-43834?

CVE-2021-43834 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-43834 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43834?

CVE-2021-43834 affects Elabftw. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43834?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-43834 published?

CVE-2021-43834 was published on 2021-12-16 and last updated on 2026-06-17.

CVE-2021-43834

CVE-2021-43834 is a critical-severity vulnerability in Elabftw with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
CVSS v2: 6.5
EPSS exploit prediction: 1% (58th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Elabftw
Published: 2021-12-16
Last modified: 2026-06-17

Description

eLabFTW is an electronic lab notebook manager for research teams. In versions prior to 4.2.0 there is a vulnerability which allows an attacker to authenticate as an existing user, if that user was created using a single sign-on authentication option such as LDAP or SAML. It impacts instances where LDAP or SAML is used for authentication instead of the (default) local password mechanism. Users should upgrade to at least version 4.2.0.

Frequently asked questions

What is CVE-2021-43834?: eLabFTW is an electronic lab notebook manager for research teams. In versions prior to 4.2.0 there is a vulnerability which allows an attacker to authenticate as an existing user, if that user was created using a single sign-on authentication option such as LDAP or SAML. It impacts instances where LDAP or SAML is used for authentication instead of the (default) local password mechanism. Users should upgrade to at least version 4.2.0.
How severe is CVE-2021-43834?: CVE-2021-43834 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-43834 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43834?: CVE-2021-43834 affects Elabftw. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43834?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-43834 published?: CVE-2021-43834 was published on 2021-12-16 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:elabftw:elabftw:*:*:*:*:*:*:*:*

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Other CWE-287 (Improper Authentication) vulnerabilities

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CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
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