CVE-2021-21291

MEDIUMNVD 4.74.7—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.7 under NVD CVSS v3. EPSS exploit probability: 1.4%, top 31% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this week
4.7
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 4.7Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

OAuth2 Proxy is an open-source reverse proxy and static file server that provides authentication using Providers (Google, GitHub, and others) to validate accounts by email, domain or group. In OAuth2 Proxy before version 7.0.0, for users that use the whitelist domain feature, a domain that ended in a similar way to the intended domain could have been allowed as a redirect. For example, if a whitelist domain was configured for ".example.com", the intention is that subdomains of example.com are allowed. Instead, "example.com" and "badexample.com" could also match. This is fixed in version 7.0.0 onwards. As a workaround, one can disable the whitelist domain feature and run separate OAuth2 Proxy instances for each subdomain.

CVSS v3
4.7
EG Score
4.7(medium)
EG Risk
—
EPSS
68.6%
KEV
Not listed

Published

February 2, 2021

Last Modified

November 21, 2024

References (8)

Affected Packages

(2 across 1 ecosystem)
Go(2)
PackageVulnerable rangeFixed inDependents
github.com/oauth2-proxy/oauth2-proxy———
github.com/oauth2-proxy/oauth2-proxy/v7—7.0.0—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 47× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

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Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-21291?
CVE-2021-21291 is a medium vulnerability published on February 2, 2021. OAuth2 Proxy is an open-source reverse proxy and static file server that provides authentication using Providers (Google, GitHub, and others) to validate accounts by email, domain or group. In OAuth2 Proxy before version 7.0.0, for users that use the whitelist domain feature, a domain that ended in…
When was CVE-2021-21291 disclosed?
CVE-2021-21291 was first published in the National Vulnerability Database on February 2, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-21291 actively exploited?
CVE-2021-21291 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 68.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-21291?
CVE-2021-21291 has a CVSS v3 base score of 4.7 (NVD).
How do I remediate CVE-2021-21291?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-21291, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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