Is there a public exploit for CVE-2026-77078?

Yes. Proof-of-concept code for CVE-2026-77078 has been published publicly.

Is there a proof of concept for CVE-2026-77078?

Yes — 1 proof-of-concept entry is linked on this page, from public repositories and community submissions. They are listed for authorised testing only.

How severe is CVE-2026-77078?

CVE-2026-77078 scores CVSS 7.5 (v3.1), rated high. EPSS puts the chance of exploitation in the next 30 days at 0.49%.

What does CVE-2026-77078 affect?

CVE-2026-77078 affects multer multer.

7.5 High

multer is a middleware for handling multipart/form-data in Node.js.

CVE-2026-77078

multer is a middleware for handling multipart/form-data in Node.js. A small multipart request containing two specially crafted text field names can cause an uncaught RangeError (Invalid array length) that terminates the Node.js process. The first field uses a very large numeric array index to allocate a maximum-length sparse array, and a second field then pushes past that length, which throws inside the append-field dependency and is not caught by multer. All versions before 2.3.0 are affected, and the issue is a remotely triggerable denial of service. The issue is fixed in multer 2.3.0. Upgrade to multer 2.3.0 to remediate.

Proof-of-concept code is published

Public PoC

Public PoCwtfkimi/CVE-2026-77078

Signals come from Exploit-DB, Metasploit, Nuclei and published proof-of-concept repositories. Their absence means nothing was found, not that nothing exists.

Assessment

CVSS: 7.5 (v3.1)
Severity: High
EPSS: 0.49% chance of exploitation in the next 30 days
Known exploited: Not listed in CISA KEV
Exploit availability: Public PoC
Published: 28 August 2026
Last updated: 2 September 2026
Affected: multer · multer
Weakness: CWE-248
Assigner: ce714d77-add3-4f53-aff5-83d477b104bb

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

At the source

References

Community proofs of concept

No community proof of concept yet. If you have one for a published vulnerability and the right to share it, add it below — it will appear here once reviewed.

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