CVE-2025-55195: Prototype Pollution (CVSS 7.3)

Description

@std/toml is the Deno Standard Library. Prior to version 1.0.9, an attacker can pollute the prototype chain in Node.js runtime and Browser when parsing untrusted TOML data, thus achieving Prototype Pollution (PP) vulnerability. This is because the library is merging an untrusted object with an empty object, which by default the empty object has the prototype chain. This issue has been patched in version 1.0.9.

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CVSS v3.1 Score

7.3

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Weakness Type (CWE)

CWE-1321 CWE-1321

References

Other References

https://github.com/denoland/std/commit/540662cfd6d71e969af292aa604ef4049dbe271b https://github.com/denoland/std/releases/tag/release-2025.08.13 https://github.com/denoland/std/security/advisories/GHSA-crjp-8r9q-2j9r https://github.com/denoland/std/security/advisories/GHSA-crjp-8r9q-2j9r

Frequently Asked Questions

What is CVE-2025-55195? +

@std/toml is the Deno Standard Library. Prior to version 1.0.9, an attacker can pollute the prototype chain in Node.js runtime and Browser when parsing untrusted TOML data, thus achieving Prototype Pollution (PP) vulnerability. This is because the library is merging an untrusted object with an empty object, which by default the empty object has the prototype chain. This issue has been patched in version 1.0.9. It has a CVSS v3.1 base score of 7.3 (HIGH).

How severe is CVE-2025-55195? +

CVE-2025-55195 has a CVSS v3.1 score of 7.3 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

How do I check if I'm vulnerable to CVE-2025-55195? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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