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VulnerabilityPublished

CVE-2025-48997: expressjs multer · Uncaught Exception

Affects expressjs multerSource CVE Database V5

0

Not known to be exploited · CVSS 8.7 High : upgrade to 2.0.1 soon.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 2.0.1
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Jun 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade expressjs multer to 2.0.1.

Affected software

ProductAffectedFixed in
npmmulterpkg:npm/multerOther threatsAffected
  • <2.0.1 >=1.4.4-lts.1
Fixed in
  • 2.0.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

The primary and most effective mitigation is to upgrade Multer to version 2.0.1 or later, where the vulnerability has been fixed. Organizations should audit their codebases and dependencies to identify usage of vulnerable Multer versions and prioritize patching. In cases where immediate upgrade is not feasible, implementing input validation at the application layer to reject multipart requests with empty field names can reduce exposure. Additionally, deploying robust process management tools such as PM2 or systemd to automatically restart crashed Node.js processes can minimize downtime. Rate limiting and web application firewalls (WAFs) configured to detect and block malformed multipart requests may provide temporary protection. Monitoring application logs for repeated crashes or suspicious upload requests can help detect exploitation attempts early. Finally, organizations should incorporate this vulnerability into their incident response plans and ensure developers are aware of secure coding practices to handle unexpected input gracefully.

Description

Multer is a node.js middleware for handling `multipart/form-data`. A vulnerability that is present starting in version 1.4.4-lts.1 and prior to version 2.0.1 allows an attacker to trigger a Denial of Service (DoS) by sending an upload file request with an empty string field name. This request causes an unhandled exception, leading to a crash of the process. Users should upgrade to `2.0.1` to receive a patch. No known workarounds are available.

References

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