CVE-2026-91143

HIGHPre-NVD 7.27.2—
EchelonGraph scoreHIGH confidence

Score 7.2 from GitHub Security Advisory published 2026-09-15. a secondary CVSS source baseline 7.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
7.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.2Exploit: None knownExposed: 0

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

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.

CVSS v3
7.2
EG Score
7.2(high)
EG Risk
37(Track)
EG Risk 37/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity72% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
19%
KEV
Not listed

Published

September 14, 2026

Last Modified

September 15, 2026

Advisory Details (5)

Auto-updated Sep 14, 2026
No patch confirmed yet.
generic

goproxy through 15.3 Authentication Bypass via CONNECT | Advisories | VulnCheck

https://www.vulncheck.com/advisories/goproxy-through-15.3-authentication-bypass-via-connect
generic

GitHub - snail007/goproxy: 🔥 Proxy is a high performance HTTP(S) proxies, SOCKS5 proxies,WEBSOCKET, TCP, UDP proxy server implemented by golang. Now, it supports chain-style proxies,nat forwarding in different lan,TCP/UDP port forwarding, SSH forwarding.Proxy是golang实现的高性能http,https,websocket,tcp,socks5代理服务器,支持内网穿透,链式代理,通讯加密,智能HTTP,SOCKS5代理,黑白名单,限速,限流量,限连接数,跨平台,KCP支持,认证API。 · GitHub

https://github.com/snail007/goproxy
generic

goproxy/services/http.go at v15.3 · snail007/goproxy · GitHub

https://github.com/snail007/goproxy/blob/v15.3/services/http.go
generic

goproxy/utils/structs.go at v15.3 · snail007/goproxy · GitHub

https://github.com/snail007/goproxy/blob/v15.3/utils/structs.go
generic

oss/goproxy.md at main · geo-chen/oss · GitHub

https://github.com/geo-chen/oss/blob/main/goproxy.md

Vendor Advisories for CVE-2026-91143(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 23× in last 7d / 23× 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.

  1. 2026-09-19 21:50 UTCEG score recompute
  2. 2026-09-19 21:50 UTCGHSA enrichment
  3. 2026-09-19 09:44 UTCGHSA enrichment
  4. 2026-09-18 21:38 UTCEG score recompute
  5. 2026-09-18 21:38 UTCGHSA enrichment
  6. 2026-09-18 19:28 UTCEPSS rescore
  7. 2026-09-18 09:32 UTCGHSA enrichment
  8. 2026-09-17 21:24 UTCEG score recompute
  9. 2026-09-17 21:24 UTCGHSA enrichment
  10. 2026-09-17 19:32 UTCEPSS rescore
  11. 2026-09-17 09:18 UTCGHSA enrichment
  12. 2026-09-16 21:12 UTCEG score recompute
  13. 2026-09-16 21:12 UTCGHSA enrichment
  14. 2026-09-16 14:09 UTCEPSS rescore
  15. 2026-09-16 08:52 UTCEG score recompute
  16. 2026-09-16 08:52 UTCGHSA enrichment
  17. 2026-09-16 05:15 UTCEPSS rescore
  18. 2026-09-15 20:46 UTCGHSA enrichment
  19. 2026-09-15 10:26 UTCEG score recompute
  20. 2026-09-15 10:26 UTCGHSA enrichment
  21. 2026-09-14 22:20 UTCEG score recompute
  22. 2026-09-14 21:54 UTCEG score recompute
  23. 2026-09-14 21:54 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-91143?
CVE-2026-91143 is a high vulnerability published on September 14, 2026. 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…
When was CVE-2026-91143 disclosed?
CVE-2026-91143 was first published in the National Vulnerability Database on September 14, 2026, with the most recent update on September 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-91143 actively exploited?
CVE-2026-91143 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 80.8% of all scored CVEs.
What is the CVSS score of CVE-2026-91143?
CVE-2026-91143 has a CVSS v3 base score of 7.2 (NVD).
How do I remediate CVE-2026-91143?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-91143, 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

Explore the affected products and dependency analysis for CVE-2026-91143

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