CVE-2026-27125

What it is

svelte performance oriented web framework. Prior to 5.51.5, in server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. Limited direct impact.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-02-20 23:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 10:26 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 5.3 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-02-20 23:16 UTC

Last modified

2026-06-17 10:26 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-915

Record status

Analyzed

Affected

• Svelte < 5.51.5

Attack profile CVSS 4.0 · 5.3

Attack vector

Network

Complexity

High

Attack requirements

Present

Privileges needed

Low

User interaction

None

Confidentiality

Low

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-27125.md and follow it. Check whether this project is affected by CVE-2026-27125. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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