CVE-2025-46653 is a low-severity (CVSS 3.1) CWE-338 vulnerability in formidable. A fix is available for formidable — see the affected versions and patch details below.
Formidable relies on hexoid to prevent guessing of filenames for untrusted executable content
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-46653.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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.
formidablenpmDescription
Formidable (aka node-formidable) 2.x before 2.1.3 and 3.x before 3.5.3 relies on hexoid to prevent guessing of filenames for untrusted executable content; however, hexoid is documented as not "cryptographically secure." (Also, there is a scenario in which only the last two characters of a hexoid string need to be guessed, but this is not often relevant.) NOTE: this does not imply that, in a typical use case, attackers will be able to exploit any hexoid behavior to upload and execute their own content.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | formidable | ≥ 3.1.1-canary.20211030&&< 3.5.3 | 3.5.3npm install formidable@3.5.3 |
| 📦npm | formidable | ≥ 2.1.0&&< 2.1.3 | 2.1.3npm install formidable@2.1.3 |
Affected Products
formidablenode-formidableDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for formidable, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update formidable to 3.5.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-46653 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.
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.
Red Hat assigned a lower CVSS score because successful exploitation requires predicting filenames generated by a non-cryptographic PRNG under specific timing conditions, which significantly increases attack complexity. Additionally, the practical impact is limited to a potential low integrity issue (e.g., file…
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for CVE-2025-46653 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2025-46653 in your dependencies?
Find it across npm, including transitive dependencies.