GHSA-g5hg-p3ph-g8qg — multer
Fix: expressjs/multer#1256GHSA-g5hg-p3ph-g8qg is a CWE-248 vulnerability in multer. A fix is available for multer — see the affected versions and patch details below.
Multer vulnerable to Denial of Service via unhandled exception
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-g5hg-p3ph-g8qg.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
multernpmDescription
Impact
A vulnerability in Multer versions >=1.4.4-lts.1, <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.
Patches
Users should upgrade to 2.0.1
Workarounds
None
References
https://github.com/expressjs/multer/commit/35a3272b611945155e046dd5cef11088587635e9 https://github.com/expressjs/multer/issues/1233 https://github.com/expressjs/multer/pull/1256
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | multer | ≥ 1.4.4-lts.1&&< 2.0.1 | 2.0.1npm install multer@2.0.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for multer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update multer to 2.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g5hg-p3ph-g8qg is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-g5hg-p3ph-g8qg can be triaged on real exposure rather than presence alone.
Tailored to GHSA-g5hg-p3ph-g8qg. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
The denial of service impact is limited to the program that integrates multer. The host operating system is not affected.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Developer Hub 1.7 | rhdh/rhdh-hub-rhel9:1.7.0-1754936470 | RHSA-2025:14090 |
Frequently Asked Questions
Is GHSA-g5hg-p3ph-g8qg in your dependencies?
O3 Security finds GHSA-g5hg-p3ph-g8qg across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.