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CriticalPublic exploit

Axios NO_PROXY loopback bypass via 127.0.0.0/8 addresses

IdentifiersCVE-2026-42043CWE-918· Server-Side Request Forgery (SSRF)

CVE-2026-42043 is an SSRF-related proxy bypass in Axios, the promise-based HTTP client for browsers and Node.js. In Axios 1.15.0, the fix for CVE-2025-62718 incompletely handled loopback destinations when applying NO_PROXY protections. The implementation normalized some host representations and treated only localhost, 127.0.0.1, and ::1 as loopback-equivalent, but failed to recognize the full IPv4 loopback range defined by RFC 1122 (127.0.0.0/8). As a result, requests to addresses such as 127.0.0.2, 127.0.0.100, or 127.1.2.3 could be misclassified as external and sent through a configured proxy instead of being excluded by NO_PROXY. This allows an attacker who can influence the target URL of an Axios request to bypass intended protections for local/internal destinations. The issue is described as an incomplete fix for CVE-2025-62718 and is fixed in Axios 1.15.1 and 0.31.1.

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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 allows bypass of Axios NO_PROXY protections for loopback destinations other than 127.0.0.1, causing requests intended for local/internal services to be routed through a proxy. This can undermine SSRF defenses, expose internal microservices or administrative interfaces, and permit interception of request metadata, headers, and bodies by an attacker-controlled proxy. Depending on the application environment, this may lead to sensitive data disclosure, credential or secret leakage, access to internal-only services, and possible downstream cloud account compromise if metadata or credential endpoints are reachable through alternate 127.x.x.x loopback addresses.

Mitigation

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

If immediate patching is not possible, do not rely on Axios 1.15.0 NO_PROXY handling to protect loopback destinations. Explicitly validate and block requests to the entire 127.0.0.0/8 range in application logic where untrusted input can influence request targets. Disable proxy use for sensitive internal requests where feasible, ensure proxy environment variables are not applied to requests targeting local services, and monitor for unexpected proxying of loopback traffic.

Remediation

Patch, then assume compromise.

Upgrade Axios to a fixed release. The provided content states the vulnerability is fixed in Axios 1.15.1 and 0.31.1. Applications using affected Axios versions should update to 1.15.1 or later on the 1.x branch, or 0.31.1 or later on the 0.x branch, and redeploy dependent services.
PUBLIC EXPLOITS

Exploits

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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
AxiosAxiosapplication

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ACTIVITY FEED

Recent activity

7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

7 SOURCESView more in app
What this page doesn’t show

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Exposure mapping

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Threat actor evidence

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Associated malware

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Detection signatures

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Vendor-by-vendor mapping

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

Social activity5

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

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2026-42043
NVD
nvd.nist.gov/vuln/detail/CVE-2026-42043
MITRE CWE · CWE-918
Server-Side Request Forgery (SSRF)
Vendor Advisory
github.com/axios/axios/security/advisories/GHSA-pmwg-cvhr-8vh7