# CVE-2026-113872: multer vulnerable to Denial of Service via a pending asynchronous fileFilter after request teardown


- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 22 Oct 2026
- **Updated:** 22 Oct 2026
- **Also known as:** CLSA-2026-1793097623, CLSA-2026-1793098630, ECHO-f4b8-4ad8-46ee, GHSA-q7qp-rjg7-q26m, ROOT-APP-NPM-CVE-2026-113872

## What is CVE-2026-113872?

CVE-2026-113872 is a high-severity vulnerability in multer, published on 22 Oct 2026. 

### Official description

multer is a middleware for Node.js that handles multipart/form-data file uploads. In versions from 2.0.0 before 2.5.0, when multer is configured with an asynchronous fileFilter, a single request can crash the Node.js process. If the request is aborted while one file's asynchronous fileFilter is still pending, the pending callback later resumes a parsing stream that multer has already torn down, and the underlying parser emits an error on a stream that no longer has an error listener, which Node raises as an unhandled error event so the process exits. Any application using multer with an asynchronous fileFilter is affected regardless of storage engine, while uploads using a synchronous fileFilter are not affected. The issue is fixed in multer 2.5.0, and users should upgrade to 2.5.0 or later. As a workaround, use a synchronous fileFilter.

Weakness: CWE-404 (Improper Resource Shutdown or Release), CWE-248 (Uncaught Exception)

## Which versions are affected by CVE-2026-113872?

2 open source packages ship an affected version, including multer.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `multer` | npm | From 2.0.0 | 2.5.0 |
| `multer` | npm | From 2.0.0 | 2.5.0 |

## How do I fix CVE-2026-113872?

Upgrade multer to 2.5.0 or later.

## Is CVE-2026-113872 being exploited?

There is no known exploitation of CVE-2026-113872 in the wild and no public exploit code.

Public exploit code:

- Write-up and proof of concept for CVE-2026-113872: multer async fileFilter process crash (DoS) (github_poc): https://github.com/santihabib/multer-CVE-2026-113872

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-113872 and fix it if it is affected.

What it is: CVE-2026-113872 is a high-severity vulnerability in multer, published on 22 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-113872 in the wild and no public exploit code.

Affected packages and fixed versions:
- multer (npm): affected from 2.0.0; fixed in 2.5.0
- multer (npm): affected from 2.0.0; fixed in 2.5.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-113872/ (Markdown: https://insights.sbomify.com/CVE-2026-113872/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-113872
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-113872
- OSV: https://osv.dev/vulnerability/CVE-2026-113872

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-113872/
Summaries are generated and may contain mistakes; the official description above is the record.