CVE-2026-6734

Home/CVE/Impact: When using Socks5ProxyAgent, undici reuses a single connection pool across different origins without verifying t

CVE

Impact: When using Socks5ProxyAgent, undici reuses a single connection pool across different origins without verifying t

Impact: When using Socks5ProxyAgent, undici reuses a single connection pool across different origins without verifying that the pool's origin matches the requested origin. All requests are dispatched through the pool connected to the first origin, regardless of the intended destination. This causes cross-origin request routing: credentials and request data intended for origin B are sent to origin A, responses from the wrong origin are trusted, and HTTPS requests may be silently downgraded to HTTP.

Impacted users are applications that use Socks5ProxyAgent (directly or via setGlobalDispatcher) and make requests to more than one origin. This was introduced in undici 7.23.0 via PR #4385 and affects all versions through 8.1.0. Patches: Upgrade to undici v7.26.0 or v8.2.0.

Workarounds: Use a separate Socks5ProxyAgent instance per origin, or avoid using Socks5ProxyAgent with multiple origins.

HIGH · CVSS 7.5 EPSS 0.00147

Schedule remediation

CVSS base score ≥ 7.0

Sigma rules0 YARA rules0

Look this up elsewhere - one-click external pivots

NVD CVE.org CISA Vulners Exploit-DB GitHub PoC VulnCheck KEV GreyNoise

▸ How to read a CVE - triage first, then detect and patch

This page is every public fact about CVE-2026-6734, cross-linked. Its job is to answer one question fast - does this need my attention now? - and then hand you the two things you do about it. Here is how an analyst reads it.

Triage: should I act now? Four signals, and they are not interchangeable:

CVSSseverity - how bad it is IF exploited, 0-10. A high CVSS alone is not urgency; a flaw can be a perfect 10 and never actually be attacked. EPSSprobability - a model’s estimate of the chance it is exploited in the next 30 days, 0-1. This is the “will it actually happen” signal. CISA KEVconfirmed - it is being exploited in the wild right now. The strongest signal on the page; KEV beats any score. Weaponisedavailability - public exploits / PoCs, and especially Metasploit modules rated Excellent / Great. Reliable, packaged exploit code means low-skill attackers can use it today.

How they combine: KEV, or a dependable Metasploit module, means patch now regardless of CVSS. High CVSS + low EPSS + no exploit is real but not an emergency - schedule it. Low CVSS but KEV-listed still gets patched now. The verdict above already weighed these for you; this is how it got there.

Then what - two workflows:

Detectwhen you cannot patch today, follow this CVE to the ATT&CK techniques it enables, then Build a SIEM detection (the green button) - author a rule, test it in Atomic, deploy it. That buys visibility while the patch waits. PatchAffected products / packages tell you if you are exposed; Fixed versions by distribution and Vendor advisories give the exact version that closes it.

Reading order for the panels below: verdict + badges, then Public exploits / Metasploit (is it weaponised), then ATT&CK techniques + Sigma / IDS rules (can I detect it), then Affected products / packages + Fixed versions (am I exposed, what patches it), then Threat actors / IOCs (who uses it), then Scoring & timeline / references (the evidence).

View attack path from CVE-2026-6734

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ATT&CK techniques

Techniques this CVE enables - linked via CWECAPECATT&CK. High◆ = named directly in ATT&CK or Nuclei templates.

T1134 · Access Token Manipulation T1134.001 · Token Impersonation/Theft T1528 · Steal Application Access Token T1539 · Steal Web Session Cookie T1550.004 · Web Session Cookie T1557.002 · ARP Cache Poisoning T1584.002 · DNS Server

▤ Build a SIEM detection for these techniques

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CAPEC attack patterns

Attack patterns this CVE enables - the bridge from weakness to ATT&CK technique.

CAPEC-CAPEC-111 · JSON Hijacking (aka JavaScript Hijacking) CAPEC-CAPEC-141 · Cache Poisoning CAPEC-CAPEC-142 · DNS Cache Poisoning CAPEC-CAPEC-160 · Exploit Script-Based APIs CAPEC-CAPEC-21 · Exploitation of Trusted Identifiers CAPEC-CAPEC-384 · Application API Message Manipulation via Man-in-the-Middle CAPEC-CAPEC-385 · Transaction or Event Tampering via Application API Manipulation CAPEC-CAPEC-386 · Application API Navigation Remapping CAPEC-CAPEC-387 · Navigation Remapping To Propagate Malicious Content CAPEC-CAPEC-388 · Application API Button Hijacking CAPEC-CAPEC-510 · SaaS User Request Forgery CAPEC-CAPEC-59 · Session Credential Falsification through Prediction

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Weakness Classification

CWE-346Origin Validation Error

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Scoring & Timeline

7.5

HIGH · CVSS v3.1 · ce714d77-add3-4f53-aff5-83d477b104bb

View on NVD

Attack Vector

Network Adjacent Local Physical

Attack Complexity

Low High

Privileges Required

None Low High

User Interaction

None Required

Scope

Unchanged Changed

Confidentiality

None Low High

Integrity

None Low High

Availability

None Low High

Published to NVD17 Jun 2026 · 06:18 PM

CVSS VectorCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

SSVC triage · cisa-vulnrichment

Exploitation

none

Automatable

Technical impact

total

SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.

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Vendor Advisories

rhsaRHSA-2026:7378Moderate
rhsaRHSA-2026:22380Moderate
rhsaRHSA-2026:22934Important

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References & Sources

Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.

https://cna.openjsf.org/security-advisories.html

https://github.com/nodejs/undici/security/advisories/GHSA-hm92-r4w5-c3mj