Description
form-data is a library for creating readable multipart/form-data streams. In versions through 4.0.5, the `field` argument to `FormData#append` and the `filename` option are concatenated verbatim into the `Content-Disposition` header without escaping carriage return (CR), line feed (LF), or double-quote (") characters. An application that passes attacker-controlled data as a field name or filename (for example, an API gateway that turns JSON object keys into multipart field names) allows the attacker to terminate the header line and inject additional headers, or to smuggle entire additional multipart parts, into the request the application forwards to a backend. This can let the attacker add or override form fields (e.g. set `is_admin=true`) seen by the downstream parser. This is an instance of CWE-93 (CRLF injection). The fix escapes CR, LF, and `"` as `%0D`, `%0A`, and `%22` in field names and filenames, matching the serialization browsers use per the WHATWG HTML multipart/form-data encoding algorithm. Exploitation requires the consuming application to use untrusted input as a field name or filename; applications that use only fixed/trusted field names are not affected. Fixed in 2.5.6, 3.0.5, and 4.0.6.
Published: 2026-06-12
Score: 8.7 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-hmw2-7cc7-3qxx form-data: CRLF injection in form-data via unescaped multipart field names and filenames
History

Tue, 30 Jun 2026 00:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat
Redhat service Mesh
CPEs cpe:/a:redhat:service_mesh:2.6::el8
cpe:/a:redhat:service_mesh:3.0::el9
cpe:/a:redhat:service_mesh:3.1::el9
cpe:/a:redhat:service_mesh:3.2::el9
cpe:/a:redhat:service_mesh:3.3::el9
Vendors & Products Redhat
Redhat service Mesh
References
Metrics threat_severity

None

threat_severity

Important


Fri, 12 Jun 2026 19:45:00 +0000

Type Values Removed Values Added
First Time appeared Form-data
Form-data form-data
Vendors & Products Form-data
Form-data form-data

Fri, 12 Jun 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 12 Jun 2026 18:45:00 +0000

Type Values Removed Values Added
Description form-data is a library for creating readable multipart/form-data streams. In versions through 4.0.5, the `field` argument to `FormData#append` and the `filename` option are concatenated verbatim into the `Content-Disposition` header without escaping carriage return (CR), line feed (LF), or double-quote (") characters. An application that passes attacker-controlled data as a field name or filename (for example, an API gateway that turns JSON object keys into multipart field names) allows the attacker to terminate the header line and inject additional headers, or to smuggle entire additional multipart parts, into the request the application forwards to a backend. This can let the attacker add or override form fields (e.g. set `is_admin=true`) seen by the downstream parser. This is an instance of CWE-93 (CRLF injection). The fix escapes CR, LF, and `"` as `%0D`, `%0A`, and `%22` in field names and filenames, matching the serialization browsers use per the WHATWG HTML multipart/form-data encoding algorithm. Exploitation requires the consuming application to use untrusted input as a field name or filename; applications that use only fixed/trusted field names are not affected. Fixed in 2.5.6, 3.0.5, and 4.0.6.
Title form-data does not escape CR/LF/quote in multipart field names and filenames (CRLF injection)
Weaknesses CWE-93
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}


Subscriptions

Form-data Form-data
Redhat Service Mesh
cve-icon MITRE

Status: PUBLISHED

Assigner: harborist

Published:

Updated: 2026-06-12T19:04:44.024Z

Reserved: 2026-06-12T17:33:29.185Z

Link: CVE-2026-12143

cve-icon Vulnrichment

Updated: 2026-06-12T19:03:56.430Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-06-12T19:16:26.560

Modified: 2026-06-16T15:42:57.150

Link: CVE-2026-12143

cve-icon Redhat

Severity : Important

Publid Date: 2026-06-12T18:01:30Z

Links: CVE-2026-12143 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-06-12T19:30:31Z

Weaknesses