When an HTTP server handler sends a 2xx response to an HTTP/1 CONNECT request and returns without hijacking the connection, the server improperly continues to read and serve requests from the connection. Since a 2xx response to an HTTP/1 CONNECT converts the connection into a tunnel, the server should not treat the connection as continuing to contain HTTP. The impact of this misbehavior is mostly limited to potential request smuggling, where an intermediate proxy considers the data on the connection to be tunneled and the server considers it to be HTTP.
CVE-2026-94439
HIGHPre-NVD 7.57.5Trending — 5 sources updated this week
EchelonGraph scoreHIGH confidence
“—” beside the score: it is equal to the CVSS score beside it.
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-10-09. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.5; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS, GitHub Security Advisory
7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 7.5Exploit: None knownExposed services: Not assessed
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5HIGHhigh confidence
- EG Risk
- 49EG Risk 49/100
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 (value × EchelonGraph’s weight)Severity75% × 45%The EG Score, 7.5 of 10.Exploitation0.3% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.3%
- EPSS %ILE
- 22nd
- KEV
- Not listed
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
October 8, 2026
Last Modified
October 9, 2026
Advisory Details (4)
Auto-updated Oct 9, 2026Patch available.
Web page
net/http: HTTP/1 server connection desynchronization after 2xx CONNECT response · Issue #81744 · golang/go · GitHub
https://go.dev/issue/81744Web page
Vendor Advisories for CVE-2026-94439(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(6 across 4 ecosystems)
Debian:14(3)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| golang-1.25 | 1.25.0-1 ... 1.25.9-1 (20 versions) |
| — |
| golang-1.26 | 1.26.0-1 ... 1.26~rc3-2 (24 versions) |
| — |
| golang-1.27 | 1.27.0-1 ... 1.27~rc3-1 (9 versions) |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| golang-1.19 | 1.19.10-1 ... 1.19.9-1 (12 versions) |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| golang-1.24 | 1.24.12-1 ... 1.24.9-1 (10 versions) |
| — |
Go(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| stdlib | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 20× in last 7d / 20× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
- 2026-10-11 19:12 UTCEG score recompute
- 2026-10-11 17:54 UTCGHSA enrichmentGHSA-2gfw-j3c5-j46w · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-11 16:27 UTCEG score recompute
- 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
- 2026-10-11 13:40 UTCEG score recompute
- 2026-10-11 05:36 UTCEG score recompute
- 2026-10-11 05:36 UTCGHSA enrichmentGHSA-2gfw-j3c5-j46w · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 22nd percentile
- 2026-10-10 17:36 UTCGHSA enrichmentGHSA-2gfw-j3c5-j46w · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-10 05:36 UTCEG score recompute
- 2026-10-10 05:36 UTCGHSA enrichmentGHSA-2gfw-j3c5-j46w · GitHub severity HIGH · GitHub CVSS 7.5
- 2026-10-09 20:08 UTCEPSS rescoreEPSS 0.2% · 7th percentile
- 2026-10-09 17:35 UTCGHSA enrichmentGHSA-2gfw-j3c5-j46w
- 2026-10-09 17:06 UTCEG score recomputeFirst assessed: 7.5 HIGH
- 2026-10-09 17:06 UTCGHSA enrichmentGHSA-2gfw-j3c5-j46w
- 2026-10-09 17:03 UTCMITRE cvelistV5CVSS v3 → 7.5 · severity → HIGH
- 2026-10-09 16:58 UTCGHSA enrichmentGHSA-2gfw-j3c5-j46w
- 2026-10-08 23:20 UTCNVD update
- 2026-10-08 22:58 UTCEG score recompute
- 2026-10-08 22:58 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-94439?
CVE-2026-94439 is a high-severity vulnerability; its CVE record was published on October 8, 2026. When an HTTP server handler sends a 2xx response to an HTTP/1 CONNECT request and returns without hijacking the connection, the server improperly continues to read and serve requests from the connection. Since a 2xx response to an HTTP/1 CONNECT converts the connection into a tunnel, the server…
When was the CVE record for CVE-2026-94439 published?
The CVE record for CVE-2026-94439 was published on October 8, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 9, 2026; the record at its source may have been updated since.
Is CVE-2026-94439 actively exploited?
CVE-2026-94439 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (22nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-94439?
CVE-2026-94439 has a CVSS v3.1 base score of 7.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-94439?
A fix for CVE-2026-94439 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-94439 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-94439
Is Your Infrastructure Affected by CVE-2026-94439?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.