VulnerabilityPublished 5 May 2026

CVE-2026-42037: Axios · CRLF Injection in multipart/form-data body via unsanitized blob.type in formDataToStream

Affects axiosSource GCVE Database

Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.15.1 when convenient.

Data as of 27 Oct 2026, 01:31 UTC

CVSS 3.1 base score

5.3Medium

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

Patch: Available – fixed in 1.15.1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
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: None: The vulnerable system can be exploited without any interaction from any user.
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: None: There is no loss of confidentiality within 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.

Affected software

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

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 version 1.15.1 that sanitizes the value.type property before interpolating it into the multipart Content-Type header, removing CRLF sequences. Users should upgrade to axios 1.15.1 or later to remediate this vulnerability. No additional mitigation steps are required if the upgrade is applied.

Description

Axios versions from 1.0.0 up to but not including 1.15.1 contain a CRLF injection vulnerability in the multipart/form-data body construction. The vulnerability arises because the value.type property of Blob/File-like objects is interpolated directly into the Content-Type header of each multipart part without sanitizing carriage return and line feed characters. This allows an attacker controlling the MIME type of an uploaded file to inject arbitrary headers into the multipart body, potentially bypassing server-side filters and confusing multipart parsers. The issue is fixed in version 1.15.1.

Impact

This vulnerability allows attackers to inject arbitrary MIME part headers into multipart/form-data bodies by controlling the MIME type of uploaded files. This can bypass server-side Content-Type filters, cause multipart parsers to misinterpret data, inject phantom form fields, and potentially exploit downstream server vulnerabilities that trust per-part headers. The vulnerability affects any Node.js application that accepts user files and reposts them via axios FormData, a common pattern in proxy services and API gateways. The widespread use of axios increases the potential impact.

Summary

The FormDataPart constructor in axios's lib/helpers/formDataToStream.js unsafely interpolates the value.type property of Blob/File-like objects into the Content-Type header of multipart/form-data parts without sanitizing CRLF sequences. While string values are sanitized to remove CRLF, the binary/blob path omits this step, enabling an attacker who controls the MIME type of a file to inject arbitrary headers into the multipart body. This injection bypasses Node.js v18+ built-in header protections because it targets the multipart body structure rather than HTTP headers. The vulnerability is exploitable via the public axios.post API with no special configuration. A proof-of-concept demonstrates injection of attacker-controlled headers into the multipart body, confirming the vulnerability. The issue affects axios versions >=1.0.0 <1.15.1 and is fixed in 1.15.1.

CWE-93Improper Neutralization of CRLF Sequences ('CRLF Injection') (opens in a new tab)
Base weaknessOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
Implementation
Avoid using CRLF as a special sequence.
Implementation
Appropriately filter or quote CRLF sequences in user-controlled input.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V1.5.1 (opens in a new tab)
Attack patterns
Command Delimiters (opens in a new tab)
Web Server Logs Tampering (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

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

WeaknessesCWE-93

Technical details

References

Community reviews

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