high · 7.5 Patched

multer vulnerable to Denial of Service via a pending asynchronous fileFilter after request teardown

CVE-2026-113872 · GHSA-q7qp-rjg7-q26m · published 23 Oct 2026

How serious is it

  • Severity: high, CVSS score 7.5 out of 10.
  • No exploit prediction (EPSS) score yet.
  • Not on the CISA list of exploited vulnerabilities.
  • No public exploit in Exploit-DB.

Is your app affected by CVE-2026-113872?

Paste this prompt into Claude Code, Cursor or any AI coding tool: it runs a free Shippable scan of your project and fixes what it finds. Built with Lovable, Bolt or v0? Scan your live app. Or upload your package file.

Who is affected

  • multer (npm) >= 2.0.0, < 2.5.0

How to check

  1. Run npm ls multer in your project to see the installed version, including copies pulled in by other packages.
  2. Or paste your lockfile into the checker: it lists every package with a known vulnerability, this one included.
  3. Or run npx shippable-dev scan localhost:3000 in your project folder. It reads your lockfile and flags this vulnerability along with every other known one.

How to fix

Copies a prompt for Claude Code, Cursor or Codex: it checks your lockfiles for this and upgrades it.
  1. Upgrade multer to 2.5.0 or later, commit the lockfile and redeploy.
  2. If a vulnerable version was live, check your logs and rotate the secrets that server could read.

The advisory

### Impact When `multer` is configured with an asynchronous `fileFilter`, a single request can crash the Node.js process. If a request is aborted (for example when one file is rejected) while another file's async `fileFilter` is still pending, the pending callback later resumes a parsing stream that multer has already torn down. busboy then emits an error on a stream that no longer has an error listener, which Node raises as an unhandled `'error'` event, and the process exits. A single unauthenticated request is enough, so any application using `multer` with an asynchronous `fileFilter` is affected, regardless of storage engine. Uploads using a synchronous `fileFilter` are not affected. ### Patches Users should upgrade to `multer` `2.5.0` or later. ### Workarounds Use a synchronous `fileFilter`.

Check your whole app

Dependencies are only half of it. Free and read-only: before you push, run npx shippable-dev scan localhost:3000 in your project folder, no account needed. For your live app, you prove it's yours with a one-line tag first.

References

Merged from GitHub Advisory Database, OSV. Last updated 26 Oct 2026. All vulnerabilities · RSS · JSON

Get alerts for new exploited vulnerabilities