GHSA-65fc-cr5f-v7r2 — js-toml
Fix: sunnyadn/js-toml@b125910GHSA-65fc-cr5f-v7r2 is a CWE-1321 vulnerability in js-toml. A fix is available for js-toml — see the affected versions and patch details below.
js-toml Prototype Pollution Vulnerability
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.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for GHSA-65fc-cr5f-v7r2.
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.
js-tomlnpmDescription
A prototype pollution vulnerability in js-toml allows a remote attacker to add or modify properties of the global Object.prototype by parsing a maliciously crafted TOML input.
Impact
The js-toml library is vulnerable to Prototype Pollution. When parsing a TOML string containing the specially crafted key __proto__, an attacker can add or modify properties on the global Object.prototype.
While the js-toml library itself does not contain known vulnerable "gadgets", this can lead to severe security vulnerabilities in applications that use the library. For example, if the consuming application checks for the existence of a property for authorization purposes (e.g., user.isAdmin), this vulnerability could be escalated to an authentication bypass. Other potential impacts in the application include Denial of Service (DoS) or, in some cases, Remote Code Execution (RCE), depending on the application's logic and dependencies.
Any application that uses an affected version of js-toml to parse untrusted input is vulnerable. The severity of the impact, ranging from unexpected behavior to a full security compromise, is dependent on the application's specific code and its handling of object properties.
Patches
This vulnerability has been patched in version 1.0.2.
All users are advised to upgrade to version 1.0.2 or later to mitigate this issue. Users of all prior versions are affected.
Workarounds
If you are unable to upgrade to a patched version, the only mitigation is to ensure that any TOML input being passed to the js-toml library is from a fully trusted source and has been validated to not contain malicious keys.
References
- This vulnerability was discovered and responsibly disclosed by siunam.
- The Proof-of-Concept can be found at this Gist: https://gist.github.com/siunam321/f3dc4d21a5a932c67b6c11d0026f5afc
- For more information on Prototype Pollution, see PortSwigger's explanation: https://portswigger.net/web-security/prototype-pollution
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | js-toml | all versions | 1.0.2npm install js-toml@1.0.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for js-toml, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update js-toml to 1.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-65fc-cr5f-v7r2 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-65fc-cr5f-v7r2 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-65fc-cr5f-v7r2. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-65fc-cr5f-v7r2 in your dependencies?
O3 Security finds GHSA-65fc-cr5f-v7r2 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.