CVE-2021-3116

HIGHNVD 7.57.5—

7.5

before_upstream_connection in AuthPlugin in http/proxy/auth.py in proxy.py before 2.3.1 accepts incorrect Proxy-Authorization header data because of a boolean confusion (and versus or).

CVSS v3: 7.5
EG Score: 7.5(medium)
EPSS: 61.7%
KEV: Not listed

Published

January 11, 2021

Last Modified

November 21, 2024

References (6)

cve@mitrehttps://cardaci.xyz/advisories/2021/01/10/proxy.py-2.3.0-broken-basic-authentication/
cve@mitrehttps://github.com/abhinavsingh/proxy.py/pull/482/commits/9b00093288237f5073c403f2c4f62acfdfa8ed46
cve@mitrehttps://pypi.org/project/proxy.py/2.3.1/#history
af854a3a-2127-422b-91ae-364da2661108https://cardaci.xyz/advisories/2021/01/10/proxy.py-2.3.0-broken-basic-authentication/
af854a3a-2127-422b-91ae-364da2661108https://github.com/abhinavsingh/proxy.py/pull/482/commits/9b00093288237f5073c403f2c4f62acfdfa8ed46
af854a3a-2127-422b-91ae-364da2661108https://pypi.org/project/proxy.py/2.3.1/#history

Affected Packages

(1 across 1 ecosystem)

PyPI(1)

Package	Vulnerable range	Fixed in	Dependents
proxy-py	0.1 ... 2.2.0 (10 versions)	2.3.1	—

Weakness Classification(1)

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

CWE-697Incorrect Comparison

Data Freshness Timeline

(refreshed 11× in last 7d / 19× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

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2026-05-26 22:26 UTCEG score recompute
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Frequently asked(5)

What is CVE-2021-3116?

CVE-2021-3116 is a high vulnerability published on January 11, 2021. beforeupstreamconnection in AuthPlugin in http/proxy/auth.py in proxy.py before 2.3.1 accepts incorrect Proxy-Authorization header data because of a boolean confusion (and versus or).

When was CVE-2021-3116 disclosed?

CVE-2021-3116 was first published in the National Vulnerability Database on January 11, 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-2021-3116 actively exploited?

CVE-2021-3116 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 61.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-3116?

CVE-2021-3116 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2021-3116?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3116, 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.

Dependency Blast Radius

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CVE-2021-3116

📅 Published

🔄 Last Modified

🔗 References (6)

Affected Packages

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-3116?

🔗 Related CVEs(same CWE)

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Published

Last Modified

References (6)

Frequently asked(5)

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