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HIGH

CVE-2026-91143

CVSS v3

7.2

HIGH

EPSS Score

0.5 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

goproxy through 15.3 fails to apply HTTP proxy basic authentication to CONNECT tunnel requests, allowing unauthenticated clients to bypass credential requirements. Attackers can issue CONNECT requests to establish tunnels through the authenticated proxy without providing credentials, enabling arbitrary TCP traffic relay and access to restricted destinations.

Technical details

Published
2026-09-14
Last Modified
2026-09-15

Frequently asked questions

What is CVE-2026-91143?

goproxy through 15.3 fails to apply HTTP proxy basic authentication to CONNECT tunnel requests, allowing unauthenticated clients to bypass credential requirements. Attackers can issue CONNECT requests to establish tunnels through the authenticated proxy without providing credentials, enabling arbitrary TCP traffic relay and access to restricted destinations.

Is CVE-2026-91143 actively exploited?

Active exploitation of CVE-2026-91143 has not been confirmed. Its EPSS score was 0.5% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-91143?

CVE-2026-91143 has a CVSS v3 base score of 7.2 (HIGH severity).

Is CVE-2026-91143 affecting your environment?

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