Which versions of Prototype Pollution are affected by CVE-2025-54803?

Organizations using js-toml face notable risk from CVE-2025-54803, a prototype pollution vulnerability rated CVSS 7.9. Exploitation could compromise the security of affected deployments.. A patch is available.

Is there a public PoC exploit available for CVE-2025-54803?

Yes, a public proof-of-concept exploit is available for CVE-2025-54803. Prioritise patching immediately. EPSS: 0.1%.

How to fix or mitigate CVE-2025-54803?

Within 30 days: Identify all affected systems and apply vendor patches as part of regular patch cycle. Vendor patch is available.

Prototype Pollution CVE-2025-54803

Q: What is the CVSS score of CVE-2025-54803?

CVE-2025-54803 has a CVSS 4.0 base score of 7.9 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.1%.

HIGH

Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution) (CWE-1321)

2025-08-05 security-advisories@github.com

Prototype Pollution Information Disclosure Js Toml

7.9

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

7.9 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:05 vuln.today

Patch released

Mar 28, 2026 - 19:05 nvd

Patch available

PoC Detected

Oct 09, 2025 - 17:32 vuln.today

Public exploit code

CVE Published

Aug 05, 2025 - 01:15 nvd

HIGH 7.9

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

1 npm packages depend on js-toml (1 direct, 0 indirect)

Ecosystem-wide dependent count for version 1.0.2.

DescriptionGitHub Advisory

js-toml is a TOML parser for JavaScript, fully compliant with the TOML 1.0.0 Spec. In versions below 1.0.2, 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. This is fixed in version 1.0.2.

AnalysisAI

js-toml is a TOML parser for JavaScript, fully compliant with the TOML 1.0.0 Spec. Rated high severity (CVSS 7.9), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

Technical ContextAI

This vulnerability is classified as Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution) (CWE-1321), which allows attackers to modify object prototypes to inject properties affecting application logic. js-toml is a TOML parser for JavaScript, fully compliant with the TOML 1.0.0 Spec. In versions below 1.0.2, 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. This is fixed in version 1.0.2. Affected products include: Sunnyadn Js-Toml. Version information: version 1.0.2..

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Freeze prototypes, validate object keys, avoid recursive merging of untrusted data.