Is CVE-2026-27122 actively exploited?

CVE-2026-27122 has no public evidence of in-the-wild exploitation as of 2026-02-23.

What is the CVSS score for CVE-2026-27122?

CVE-2026-27122 has a CVSS score of 5.1 (MEDIUM severity). Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N/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.

How do I patch CVE-2026-27122?

Patch guidance is available from svelte security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-27122.

CVE-2026-27122 - remediation guidance & executive summary

Description

svelte performance oriented web framework. Prior to 5.51.5, when using <svelte:element this={tag}> in server-side rendering, the provided tag name is not validated or sanitized before being emitted into the HTML output. If the tag string contains unexpected characters, it can result in HTML injection in the SSR output. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5.

CVSS Metrics

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N/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
Complexity: high
Privileges: high
User Action: none
Confidentiality: undefined
Integrity: undefined
Availability: undefined
Weaknesses: CWE-79 · Cross-site Scripting (XSS)

Metadata

Primary Vendor: SVELTE
Published: 2/20/2026
Last Modified: 2/23/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

CVE-2026-27122

Description

CVSS Metrics

Metadata

Affected Products

Remediation Guidance

Executive Summary