CRLF header injection in a widely used library could impact many apps and disrupt IT operations if exploited.
CVE-2026-12143
CRLF injection in form-data field/filename enables header tampering.
Is CVE-2026-12143 being exploited?
Not confirmed. CVE-2026-12143 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.53% probability of exploitation in the next 30 days.
How severe is CVE-2026-12143?
CVE-2026-12143 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-12143?
Yes. A fix has been recorded for CVE-2026-12143. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-12143 affect?
CVE-2026-12143 affects form-data library (Node.js) <= 4.0.5. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-12143?
Upgrade to 4.0.6+ or 2.5.6/3.0.5
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker-controlled field/filename can inject or override headers or multipart parts in requests, enabling downstream privilege escalation or data tampering.
Patch when possible
- affected< 2.5.6
- affected>= 3.0.0 and < 3.0.5
- affected>= 4.0.0 and < 4.0.6
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.