CVE-2026-42042VulnerabilityPublished 5 May 2026

Axios: XSRF Token Cross-Origin Leakage via Prototype Pollution Gadget in `withXSRFToken` Boolean Coercion

Affects axiosSource GCVE Database

Not known to be exploited · CVSS 5.4 Medium : upgrade to 1.15.1 when convenient.

Data as of 27 Oct 2026, 01:30 UTC

CVSS 3.1 base score

5.4Medium

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:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
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: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
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: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on 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 corrects the boolean coercion logic for the `withXSRFToken` property. Users should upgrade to these fixed versions to remediate the vulnerability. No additional mitigations are required if the patch is applied. If upgrading is not immediately possible, ensure that prototype pollution vulnerabilities are mitigated in dependencies and avoid misconfiguring `withXSRFToken` with non-boolean truthy values.

Description

Axios contains a vulnerability in its XSRF token protection logic where the `withXSRFToken` configuration property is coerced using JavaScript truthy/falsy semantics rather than strict boolean checks. This flaw allows prototype pollution or misconfiguration to cause the same-origin check to be bypassed, resulting in XSRF tokens being sent to cross-origin servers, potentially controlled by attackers. The vulnerability affects all Axios versions from 1.0.0 up to but not including 1.15.1, and all versions before 0.31.1. It is limited to browser environments and enables theft of anti-CSRF tokens, which can facilitate CSRF attacks but does not directly compromise session tokens. A fix is available in versions 1.15.1 and 0.31.1.

Impact

The vulnerability allows an attacker to obtain the victim's anti-CSRF token by causing Axios to send it to arbitrary cross-origin servers. This token leakage enables the attacker to bypass CSRF protections on the victim application, facilitating CSRF attacks. The impact is limited to confidentiality and integrity of the anti-CSRF token and does not affect session tokens or availability. The vulnerability requires the victim to use a browser with Axios making cross-origin requests and for prototype pollution or misconfiguration to occur. The scope remains unchanged within the browser context.

Summary

The Axios library's XSRF token protection uses a non-strict boolean check on the `withXSRFToken` config property. When this property is set to any truthy non-boolean value—such as via prototype pollution of `Object.prototype.withXSRFToken`—the same-origin check (`isURLSameOrigin`) is bypassed. This causes the XSRF token to be sent with all requests, including cross-origin requests, potentially leaking the token to attacker-controlled servers. The vulnerability is present in browser environments where the standard browser environment flag is true. The flaw arises because non-boolean truthy values short-circuit the conditional logic, skipping the intended origin verification. This can be triggered without direct user input if prototype pollution occurs. The vulnerability is tracked as CVE-2026-42042 with a CVSS 3.1 score of 5.4 (Medium). Fixed versions are 1.15.1 and 0.31.1.

CWE-183Permissive List of Allowed Inputs (opens in a new tab)
Base weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are explicitly allowed by policy because the inputs are assumed to be safe, but the list is too permissive - that is, it allows an input that is unsafe, leading to resultant weaknesses.
OWASP Cheat Sheets
Secure Design Principles (opens in a new tab)
Attack patterns
Double Encoding (opens in a new tab)
Using Leading 'Ghost' Character Sequences to Bypass Input Filters (opens in a new tab)
Exploiting Multiple Input Interpretation Layers (opens in a new tab)
Using Unicode Encoding to Bypass Validation Logic (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-201Insertion of Sensitive Information Into Sent Data (opens in a new tab)
Base weaknessOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.
Requirements
Specify which data in the software should be regarded as sensitive. Consider which types of users should have access to which types of data.
Implementation
Ensure that any possibly sensitive data specified in the requirements is verified with designers to ensure that it is either a calculated risk or mitigated elsewhere.
System Configuration
Setup default error messages so that unexpected errors do not disclose sensitive information.
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Choosing Message Identifier (opens in a new tab)
Exploiting Incorrectly Configured SSL/TLS (opens in a new tab)
WiFi MAC Address Tracking (opens in a new tab)
WiFi SSID Tracking (opens in a new tab)
Cellular Broadcast Message Request (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, 01:30 UTC

WeaknessesCWE-183, CWE-201

Technical details

References

Community reviews

Related threats