Unrated

Cross-origin request routing in undici Socks5ProxyAgent

IdentifiersCVE-2026-6734CWE-441

CVE-2026-6734 is a vulnerability in undici's Socks5ProxyAgent in which the client reuses a single connection pool across different origins without validating that the pool's origin matches the requested destination. As a result, after the first origin establishes the pooled connection, subsequent requests for other origins can be dispatched through that same pool regardless of their intended target. This leads to cross-origin request routing, where traffic intended for origin B may be sent to origin A. The issue was introduced in undici 7.23.0 via PR #4385 and affects versions through 8.1.0. Impacted deployments are applications that use Socks5ProxyAgent directly or via setGlobalDispatcher and issue requests to more than one origin.

For your environment

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can cause credentials, headers, request bodies, and other sensitive request data intended for one origin to be sent to a different origin. Applications may also trust and process responses returned from the wrong origin, creating integrity and confidentiality risks. The advisory further notes that HTTPS requests may be silently downgraded to HTTP, which can remove transport security expectations and expose traffic to interception or manipulation.

Mitigation

If you can’t patch tonight, do this now.

Until patched versions can be deployed, use a separate Socks5ProxyAgent instance per origin so pools are not shared across destinations, or avoid using Socks5ProxyAgent with multiple origins. Avoid configuring a single global dispatcher for multi-origin traffic if it causes shared agent reuse.

Remediation

Patch, then assume compromise.

Upgrade undici to a fixed release. The provided content states patched versions are 7.26.0 or 8.2.0; the advisory text states 7.28.0 or 8.2.0 or later fixed releases. Based on the available information, upgrading to 8.2.0 or later is clearly indicated, and for the 7.x branch a fixed release in the 7.26.0+ to 7.28.0+ range is referenced. Verify against the vendor's official release notes and deploy the latest supported fixed version.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

NodejsUndiciapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

6 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

6 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity6

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-6734

NVD

nvd.nist.gov/vuln/detail/CVE-2026-6734

MITRE CWE · CWE-441

cwe.mitre.org