CVE-2026-12143

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.
References
Link Resource
https://cwe.mitre.org/data/definitions/93.html
https://github.com/form-data/form-data/commit/64190db548c0179e37206858e39f27cf513e9435
https://github.com/form-data/form-data/commit/be3f3cf553978bac15a5182f1f3c3d2d38ccf229
https://github.com/form-data/form-data/commit/c7133499c2ee1b80c678e411244f4442bf902045
https://github.com/form-data/form-data/security/advisories/GHSA-hmw2-7cc7-3qxx
https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#multipart-form-data
https://www.npmjs.com/package/form-data
https://access.redhat.com/errata/RHSA-2026:33155
https://access.redhat.com/errata/RHSA-2026:33160
https://access.redhat.com/errata/RHSA-2026:33163
https://access.redhat.com/errata/RHSA-2026:33173
https://access.redhat.com/errata/RHSA-2026:33183
https://access.redhat.com/errata/RHSA-2026:34342
https://access.redhat.com/errata/RHSA-2026:36319
https://access.redhat.com/errata/RHSA-2026:36625
https://access.redhat.com/errata/RHSA-2026:36754
https://access.redhat.com/errata/RHSA-2026:40262
https://access.redhat.com/errata/RHSA-2026:41031
https://access.redhat.com/errata/RHSA-2026:41066
https://access.redhat.com/errata/RHSA-2026:41928
https://access.redhat.com/errata/RHSA-2026:41929
https://access.redhat.com/errata/RHSA-2026:41951
https://access.redhat.com/errata/RHSA-2026:42146
https://access.redhat.com/security/cve/CVE-2026-12143
https://bugzilla.redhat.com/show_bug.cgi?id=2488480
https://github.com/form-data/form-data/security/advisories/GHSA-hmw2-7cc7-3qxx
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12143.json
Configurations

No configuration.

History

21 Jul 2026, 12:17

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:41928 -
  • () https://access.redhat.com/errata/RHSA-2026:41929 -
  • () https://access.redhat.com/errata/RHSA-2026:41951 -
  • () https://access.redhat.com/errata/RHSA-2026:42146 -

17 Jul 2026, 13:17

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:41031 -
  • () https://access.redhat.com/errata/RHSA-2026:41066 -

16 Jul 2026, 12:17

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:40262 -

15 Jul 2026, 02:18

Type Values Removed Values Added
References
  • {'url': 'https://access.redhat.com/errata/RHSA-2026:37577', 'source': '0b0ca135-0b70-47e7-9f44-1890c2a1c46c'}

13 Jul 2026, 13:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:37577 -

09 Jul 2026, 13:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:36754 -

08 Jul 2026, 13:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:36319 -
  • () https://access.redhat.com/errata/RHSA-2026:36625 -

02 Jul 2026, 12:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:34342 -

30 Jun 2026, 03:17

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:33155 -
  • () https://access.redhat.com/errata/RHSA-2026:33160 -
  • () https://access.redhat.com/errata/RHSA-2026:33163 -
  • () https://access.redhat.com/errata/RHSA-2026:33173 -
  • () https://access.redhat.com/errata/RHSA-2026:33183 -
  • () https://access.redhat.com/security/cve/CVE-2026-12143 -
  • () https://bugzilla.redhat.com/show_bug.cgi?id=2488480 -
  • () https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12143.json -

12 Jun 2026, 20:16

Type Values Removed Values Added
References () https://github.com/form-data/form-data/security/advisories/GHSA-hmw2-7cc7-3qxx - () https://github.com/form-data/form-data/security/advisories/GHSA-hmw2-7cc7-3qxx -

12 Jun 2026, 19:16

Type Values Removed Values Added
New CVE

Information

Published : 2026-06-12 19:16

Updated : 2026-07-21 12:17


NVD link : CVE-2026-12143

Mitre link : CVE-2026-12143

CVE.ORG link : CVE-2026-12143


JSON object : View

Products Affected

No product.

CWE
CWE-93

Improper Neutralization of CRLF Sequences ('CRLF Injection')