How severe is CVE-2021-43812?

CVE-2021-43812 has a CVSS 3.x base score of 6.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-43812 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43812?

CVE-2021-43812 affects Auth0 Nextjs-auth0. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43812?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-43812 published?

CVE-2021-43812 was published on 2021-12-16 and last updated on 2026-06-17.

CVE-2021-43812

CVE-2021-43812 is a medium-severity vulnerability in Auth0 Nextjs-auth0 with a CVSS 3.x base score of 6.4. 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-601.

Key facts

Severity: Medium (CVSS 3.x base score 6.4)
CVSS v2: 5.8
EPSS exploit prediction: 1% (47th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-601
Affected product: Auth0 Nextjs-auth0
Published: 2021-12-16
Last modified: 2026-06-17

Description

The Auth0 Next.js SDK is a library for implementing user authentication in Next.js applications. Versions before 1.6.2 do not filter out certain returnTo parameter values from the login url, which expose the application to an open redirect vulnerability. Users are advised to upgrade as soon as possible. There are no known workarounds for this issue.

Frequently asked questions

What is CVE-2021-43812?: The Auth0 Next.js SDK is a library for implementing user authentication in Next.js applications. Versions before 1.6.2 do not filter out certain returnTo parameter values from the login url, which expose the application to an open redirect vulnerability. Users are advised to upgrade as soon as possible. There are no known workarounds for this issue.
How severe is CVE-2021-43812?: CVE-2021-43812 has a CVSS 3.x base score of 6.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-43812 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (47th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43812?: CVE-2021-43812 affects Auth0 Nextjs-auth0. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43812?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-43812 published?: CVE-2021-43812 was published on 2021-12-16 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:auth0:nextjs-auth0:*:*:*:*:*:node.js:*:*

More vulnerabilities in Auth0 Nextjs-auth0

CVE-2021-32702 — High (CVSS 8.0): The Auth0 Next.js SDK is a library for implementing user authentication in Next.js applications. Versions before and…
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Other CWE-601 (Open Redirect) vulnerabilities

CVE-2018-3774 — Critical (CVSS 10.0): Incorrect parsing in url-parse <1.4.3 returns wrong hostname which leads to multiple vulnerabilities such as SSRF, Open…
CVE-2019-25282 — Critical (CVSS 9.8): V-SOL GPON/EPON OLT Platform v2.03 contains an open redirect vulnerability in the script that allows attackers to…
CVE-2020-36912 — Critical (CVSS 9.8): Plexus anblick Digital Signage Management 3.1.13 contains an open redirect vulnerability in the 'PantallaLogin' script…
CVE-2025-43526 — Critical (CVSS 9.8): This issue was addressed with improved URL validation. This issue is fixed in Safari 26.2, macOS Tahoe 26.2. On a Mac…
CVE-2025-55031 — Critical (CVSS 9.8): Malicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passkey transport. An…
CVE-2024-22891 — Critical (CVSS 9.8): Nteract v.0.28.0 was discovered to contain a remote code execution (RCE) vulnerability via the Markdown link.

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