VulnerabilityPublished 5 May 2026

CVE-2026-42038: Axios · no_proxy bypass via IP alias allows SSRF

Affects axiosSource GCVE Database

Not known to be exploited · CVSS 6.8 Medium : upgrade to 1.15.1 when convenient.

Data as of 27 Oct 2026, 01:31 UTC

CVSS 3.1 base score

6.8Medium

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 1.15.1, 0.31.1

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 5 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade axios to 1.15.1; axios to 0.31.1.

Affected software

Product	Affected	Fixed in
npmaxios	Affected >=1.0.0 <1.15.1	Fixed in 1.15.1
npmaxios	Affected <0.31.1	Fixed in 0.31.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available in Axios versions 1.15.1 and 0.31.1 that fixes the no_proxy bypass by resolving loopback IP aliases correctly. Users should upgrade to these fixed versions to mitigate the vulnerability. No additional mitigation is required if these versions are in use.

Description

Axios versions prior to 1.15.1 and 0.31.1 contain a vulnerability in the no_proxy environment variable handling that allows bypassing proxy restrictions via IP aliasing. Specifically, when no_proxy=localhost is set, requests to 127.0.0.1 and [::1] do not bypass the proxy as intended, due to the shouldBypassProxy() function performing only string matching without resolving loopback IP aliases. This can lead to server-side request forgery (SSRF) risks where an attacker can route internal requests through a malicious proxy.

Impact

An attacker able to influence URLs in server-side environments using Axios with no_proxy restrictions can bypass these restrictions by using IP aliases instead of hostnames. This allows routing requests through an attacker-controlled proxy, potentially exposing internal services or cloud metadata endpoints. The vulnerability can lead to high confidentiality impact due to data leakage, but does not affect integrity or availability.

Summary

The Axios HTTP client has a vulnerability (CVE-2026-42038) where the no_proxy environment variable bypass intended to prevent proxying requests to internal addresses is incomplete. The shouldBypassProxy() function does not normalize or resolve IP aliases such as localhost, 127.0.0.1, and ::1 equivalently. Consequently, setting no_proxy=localhost does not block requests to 127.0.0.1 or ::1, allowing these requests to be routed through an attacker-controlled proxy. This can be exploited in server-side environments to bypass protections against accessing internal or cloud metadata services, potentially leaking sensitive internal data. The issue is fixed in Axios versions 1.15.1 and 0.31.1 by enhancing the proxy bypass logic to treat loopback aliases equivalently.

CWE-918Server-Side Request Forgery (SSRF) (opens in a new tab)
Base weaknessCWE Top 25 (2025): #22OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.6.1 (opens in a new tab)
V5.2.6 (opens in a new tab)
Attack patterns
Server Side Request Forgery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Oct 2026, 01:31 UTC

WeaknessesCWE-918

Technical details

References

Community reviews

Related threats