VDB-347263 · CVE-2026-27122 · GHSA-m56q-vw4c-c2cp

sveltejs svelte up to 5.51.4 cross site scripting

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
2.3	$0-$5k	0.00

Summaryinfo

A vulnerability was found in sveltejs svelte up to 5.51.4. It has been rated as problematic. This issue affects some unknown processing. This manipulation causes cross site scripting. This vulnerability appears as CVE-2026-27122. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in sveltejs svelte up to 5.51.4. It has been declared as problematic. Affected by this vulnerability is an unknown function. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-80. The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special characters such as "<", ">", and "&" that could be interpreted as web-scripting elements when they are sent to a downstream component that processes web pages. As an impact it is known to affect integrity. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-27122 since 02/17/2026. The exploitation appears to be easy. The attack can be launched remotely. Additional levels of successful authentication are necessary for exploitation. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 5.51.5 eliminates this vulnerability.

Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Vendor

sveltejs

Name

svelte

Version

Website

Product: https://github.com/sveltejs/svelte/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 2.4
VulDB Meta Temp Score: 2.3

VulDB Base Score: 2.4
VulDB Temp Score: 2.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross site scripting
CWE: CWE-80 / CWE-74 / CWE-707
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: svelte 5.51.5

Timelineinfo

02/17/2026 CVE reserved
02/21/2026 +4 days Advisory disclosed
02/21/2026 +0 days VulDB entry created
02/22/2026 +1 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-m56q-vw4c-c2cp
Status: Confirmed

CVE: CVE-2026-27122 (🔒)
GCVE (CVE): GCVE-0-2026-27122
GCVE (VulDB): GCVE-100-347263

Entryinfo

Created: 02/21/2026 05:54
Updated: 02/22/2026 20:54
Changes: 02/21/2026 05:54 (67), 02/22/2026 20:54 (2)
Complete: 🔍
Cache ID: 216::103