CVE-2026-12143

form-data does not escape CR/LF/quote in multipart field names and filenames (CRLF injection)

Published Jun 12, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

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
References
Link Providers
https://access.redhat.com/errata/RHSA-2026:33155 cve-icon
https://access.redhat.com/errata/RHSA-2026:33160 cve-icon
https://access.redhat.com/errata/RHSA-2026:33163 cve-icon
https://access.redhat.com/errata/RHSA-2026:33173 cve-icon
https://access.redhat.com/errata/RHSA-2026:33183 cve-icon
https://access.redhat.com/errata/RHSA-2026:34342 cve-icon
https://access.redhat.com/errata/RHSA-2026:36319 cve-icon
https://access.redhat.com/errata/RHSA-2026:36625 cve-icon
https://access.redhat.com/errata/RHSA-2026:36754 cve-icon
https://access.redhat.com/errata/RHSA-2026:40262 cve-icon
https://access.redhat.com/errata/RHSA-2026:41031 cve-icon
https://access.redhat.com/errata/RHSA-2026:41066 cve-icon
https://access.redhat.com/errata/RHSA-2026:41928 cve-icon
https://access.redhat.com/errata/RHSA-2026:41929 cve-icon
https://access.redhat.com/errata/RHSA-2026:41951 cve-icon
https://access.redhat.com/errata/RHSA-2026:42146 cve-icon
https://access.redhat.com/errata/RHSA-2026:42796 cve-icon
https://access.redhat.com/errata/RHSA-2026:43052 cve-icon
https://access.redhat.com/errata/RHSA-2026:44263 cve-icon
https://access.redhat.com/errata/RHSA-2026:44267 cve-icon
https://access.redhat.com/errata/RHSA-2026:48124 cve-icon
https://access.redhat.com/errata/RHSA-2026:48151 cve-icon
https://access.redhat.com/errata/RHSA-2026:48693 cve-icon
https://access.redhat.com/errata/RHSA-2026:50300 cve-icon
https://access.redhat.com/errata/RHSA-2026:54770 cve-icon
https://access.redhat.com/errata/RHSA-2026:56338 cve-icon
https://access.redhat.com/errata/RHSA-2026:56366 cve-icon
https://access.redhat.com/errata/RHSA-2026:56431 cve-icon
https://access.redhat.com/errata/RHSA-2026:57013 cve-icon
https://access.redhat.com/errata/RHSA-2026:57545 cve-icon
https://access.redhat.com/errata/RHSA-2026:57590 cve-icon
https://access.redhat.com/errata/RHSA-2026:57801 cve-icon
https://access.redhat.com/errata/RHSA-2026:59136 cve-icon
https://access.redhat.com/errata/RHSA-2026:59153 cve-icon
https://access.redhat.com/errata/RHSA-2026:59155 cve-icon
https://access.redhat.com/errata/RHSA-2026:59556 cve-icon
https://access.redhat.com/errata/RHSA-2026:59557 cve-icon
https://access.redhat.com/errata/RHSA-2026:59558 cve-icon
https://access.redhat.com/errata/RHSA-2026:59559 cve-icon
https://access.redhat.com/errata/RHSA-2026:59579 cve-icon
https://access.redhat.com/errata/RHSA-2026:60387 cve-icon
https://access.redhat.com/errata/RHSA-2026:60388 cve-icon
https://access.redhat.com/errata/RHSA-2026:60389 cve-icon
https://access.redhat.com/errata/RHSA-2026:60390 cve-icon
https://access.redhat.com/errata/RHSA-2026:60391 cve-icon
https://access.redhat.com/errata/RHSA-2026:60446 cve-icon
https://access.redhat.com/errata/RHSA-2026:60477 cve-icon
https://access.redhat.com/errata/RHSA-2026:60520 cve-icon
https://access.redhat.com/errata/RHSA-2026:62260 cve-icon
https://access.redhat.com/errata/RHSA-2026:63047 cve-icon
https://access.redhat.com/errata/RHSA-2026:63355 cve-icon
https://access.redhat.com/errata/RHSA-2026:63373 cve-icon
https://access.redhat.com/errata/RHSA-2026:66003 cve-icon
https://access.redhat.com/errata/RHSA-2026:66488 cve-icon
https://access.redhat.com/errata/RHSA-2026:66545 cve-icon
https://access.redhat.com/security/cve/CVE-2026-12143 cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2488480 cve-icon
https://cwe.mitre.org/data/definitions/93.html cve-icon cve-icon cve-icon
https://github.com/form-data/form-data/commit/64190db548c0179e37206858e39f27cf513e9435 cve-icon cve-icon cve-icon
https://github.com/form-data/form-data/commit/be3f3cf553978bac15a5182f1f3c3d2d38ccf229 cve-icon cve-icon cve-icon
https://github.com/form-data/form-data/commit/c7133499c2ee1b80c678e411244f4442bf902045 cve-icon cve-icon cve-icon
https://github.com/form-data/form-data/security/advisories/GHSA-hmw2-7cc7-3qxx cve-icon cve-icon cve-icon cve-icon
https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#multipart-form-data cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-12143 cve-icon
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12143.json cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-12143 cve-icon
https://www.npmjs.com/package/form-data cve-icon cve-icon cve-icon
History
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

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

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

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
harborist
Published
Updated
Sep 11, 2026, 12:08 PM
Reserved
Jun 12, 2026, 5:33 PM
Status
Awaiting Analysis
Published
Jun 12, 2026, 7:16 PM
Modified
Sep 11, 2026, 1:17 PM
Severity
Important
Public date
Jun 12, 2026, 6:01 PM